Lattice 2001

Here is another list, sorted by parallel and poster sessions.

 A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  R  S  T  U  V  W  Y  Z

1	Aarts, Gert	aarts@thphys.uni-heidelberg.de	top
	Gert Aarts
	Spectral function at high temperature
	At high temperature the infrared modes of a weakly coupled quantum field theory are treated well in the classical field approximation. I use this to calculate spectral functions at finite temperature directly in real time.
	parallel talk	Non-zero temperature and density   6
2	Alexandrou, Constantia	alexand@ucy.ac.cy	top
	C. Alexandrou, Ph. de Forcrand, A. Tsapalis
	Static three and four quark potentials
	We present results on the static three quark and four quark potentials in SU(3) and SU(4) respectively. We use the multi-hit procedure for the time links and a variational approach to determine the ground state. We compare our results to the Y- and Delta ansaetze.
	parallel talk	Heavy quark physics   5
3	Allton, Chris	c.allton@swan.ac.uk	top
	C.R. Allton
	Searching for Dynamical Fermion effects in UKQCD simulations.
	We present recent results from the UKQCD collaboration's dynamical QCD simulations. This data has fixed lattice spacing but varying dynamical quark mass. We concentrate on searching for an unquenching signal in the hadronic mass spectrum.
	parallel talk	QCD spectrum and quark masses   1
4	Ambjorn, Jan	ambjorn@nbi.dk	top
	J. Ambjorn, J. Jurkiewicz and R. Loll
	Simulations of generalized 3d Lorentzian gravity
	We consider a generalized model of 3d Lorentzian quantum gravity which include certain classes of degenerate geometries which appear naturally in a matrix model formulation of 3d Lorentzian quantum gravity. Computer simulations show the emergence of a ``semiclassical'' 3d extended geometries despite the explicit background independence of the model.
	parallel talk	Quantum gravity and random surfaces   2
5	Ambjorn, Jan	ambjorn@nbi.dk	top
	J. Ambjorn, K. Anagnostopoulos and A. Krasnitz
	High temperature, classical, real time dynamics of non-abelian gauge theories as seen by the computer
	We test at the electroweak scale the recently proposed elaborate theoretical scenario for real time high temperature thermal non-abelian gauge theories. We see nothing of the predicted behavior. This indicates that perturbative concepts like color conductivity and Landau damping might be irrelevant at temperatures corresponding to the electroweak scale.
	poster	Non-zero temperature and density
6	ambjorn, jan	ambjorn@nbi.dk	top
	jan ambjorn
	Quantum gravity, string theory and non-commutative gauge theory seen from the lattice
	[plenary talk]
	plenary talk
7	Anagnostopoulos, Konstantinos	konstant@physics.uoc.gr	top
	J. Ambjorn, K.N. Anagnostopoulos, W. Bietenholz,F. Hofheinz, J. Nishimura, P. Olesen
	The Quantum Geometry of String Theory
	The IKKT matrix model is thought to provide a model for a non-perturbative definition of type IIB string theory. One of its attractive feature is the possibility to obtain spacetime dynamically from the model. We discuss recent numerical results related to the properties of quantum spacetime.
	parallel talk	Quantum gravity and random surfaces   1
8	Aoki, Sinya	saoki@het.ph.tsukuba.ac.jp	top
	CP-PACS Collaboration: S.~Aoki, {\it et al.}
	Non-Perturbative renormalizations in domain-wall QCD by Schr\"odinger functional scheme
	We try to evaluate non-perturbative renormalization factors such as $Z_V$, $Z_A$,d$Z_P$ and $Z_{BK}$ in domain-wall QCD (DWQCD) via the Schr\"odinger functional (SF) scheme. After setting up the SF scheme in DWQCD, we have performed several tests for our method, which include the dependence of our results on $M$(the domain-wall height) and $N_s$(a number of sites in the fifith dimension). Our results for $Z_V$ and $Z_A$ are given in quenched DWQCD with RG improved as well as plaquette gauge actions. We compare them with those obtained at 1-loop in the perturbation theory.
	poster	Improvement and renormalization
9	Aoki, Yasumichi	yaoki@bnl.gov	top
	Yasumichi Aoki for RIKEN-BNL-Columbia Collaboration
	Hadron spectrum for quenched domain-wall fermions with DBW2 gauge action
	We study the basic physical quantities of quenched domain-wall QCD with the renormalization group improved, DBW2 gauge action of the QCD Taro group. Hadron masses are systematically examined for a range of parameters. Application to hadronic matrix elements is also discussed.
	parallel talk	QCD spectrum and quark masses   4
10	Arkin, Handan	handan@hacettepe.edu.tr	top
	H. Ark{\i}n and T. \c{C}elik
	Spinodal Decomposition in 3-D 3-state Potts Model
	We have simulated the q=3 state Potts Model in three dimensions and examined the time evolutions of oriented clusters formed following a rapid temperature quench (1). We have studied the phase conversion mechanism after a deep temperature quench and concluded that it is spinodal decomposition while a rather shallow quench to temperatures near the phase transition point proceeds through usual nucleation (2, 3). References 1. H. Ark{\i}n and T. \c{C}elik, Int. J. of Mod. Phys. 11, 2000, 1313. 2. H. Ark{\i}n, T. \c{C}elik, B. A. Berg, H. Meyer-Ortmanns, Int. J. of Mod. Phys. 10, 1999, 1261. 3. J. Borril and M. Gleiser, Phys. Rev. D 51, 1995,4111.
	poster	Spin models
11	Atsushi, Yamada	atsushi@physics.s.chiba-u.ac.jp	top
	Atsushi Yamada
	A physical interpretation of the eigenmodes of the lattice Ginsparg Wilson type Dirac operator
	We pursue Ginsparg and Wilsons' block spin approach in the derivation of the Ginsparg-Wilson relation and study the correspondence of the eigenmodes of the Dirac operators in the continuum and lattice theories. After introducing a suitable cut-off in the continuum theory, we identify unphysical modes of the lattice Dirac operator which do not correspond to any physical modes of the regulated continuum Dirac operator. We also consider zero modes in the continuum and lattice theories. Our studies give a physical interpretation of the expression of the index defined on a lattice and a formal argument on the relation of the indices between the continuum and lattice theories.
	parallel talk	Chiral fermions and gauge theories   1
12	Azakov, Siyavush	azakov_s@hotmail.com	top
	Azakov S.
	The General Correlation Function in the Schwinger Model on a Torus
	In the framework of the Euclidean path integral approach we derive the exact general formula for the N-point chiral densities correlator in the Schwinger model on a torus.
	poster	Topology and confinement
13	Baer, Oliver	obaer@lns.mit.edu	top
	O. Baer, R. Brower, B. Schlittgen, U.-J. Wiese
	The Large N_c Limit of Quantum Link Models
	In the quantum link formulation of SU(N_c) lattice Yang-Mills theory the gluons are collective excitations of discrete quantum links, propagating in a fifth Euclidean dimension, which eventually disappears by dimensional reduction. In contrast to the standard formulation, a quantum link can be viewed as a composite object, consisting of two rishon fermions. This leads to a completely new approach towards calculating the large N_c limit of gauge theories. By contracting the color indices of rishons belonging to two different quantum links, one can formulate the theory entirely in terms of color neutral Phi-fields. Rishons also carry a flavor index, which varies between 1 and M, the number of rishon flavors. The resulting theory of Phi-fields is a rishon flavor gauge theory with U(M) gauge transformations on the links of the lattice. In order to obtain a large N_c limit which corresponds to the 't Hooft limit, M also needs to be taken to infinity. For any finite M and at strong coupling the theory exhibits an area law for the Wilson loop and therefore shows confinement.
	poster	Theoretical developments
14	Bakeyev, Timour	bakeev@thsun1.jinr.ru	top
	T. Bakeyev
	A new method for Monte Carlo simulation of theories with Grassmann variables.
	A new algorithm for simulation of theories with dynamical fermions is presented. Its application to the models of physical interest is discussed.
	poster	Algorithms and machines
15	Bali, Gunnar	g.bali@physics.gla.ac.uk	top
	Gunnar Bali, Peter Boyle, Christine Davies
	Where do perturbative and non-perturbative Lattice QCD meet?
	We relate recent perturbative calculations of Wilson loops and the lattice potential to results from numerical simulations of QCD with and without sea quarks of a variety of masses and actions. The reliability of "boosted" perturbation theory techniques is investigated and estimates for the QCD running coupling, the static quark self energy and the "beta shifts" that are induced when changing the quark mass in lattice simulations are given.
	parallel talk	Improvement and renormalization   1
16	Barresi, Andrea	barresi@physik.hu-berlin.de	top
	A. Barresi, G. Burgio, M. Mueller-Preussker
	Finite temperature phase transition, adjoint Polyakov loop and topology in SU(2) LGT
	We investigate the phase structure of pure SU(2) lattice gauge theory at finite temperature in the mixed fundamental and adjoint representation modified with a Z(2) monopole chemical potential. The decoupling of the finite temperature phase transition from unphysical zero temperature bulk phase transitions is analyzed with special emphasis on the continuum limit. The possible relation of the adjoint Polyakov loop as an order parameter for the finite temperature phase transition with the topological structure of the theory is discussed.
	parallel talk	Non-zero temperature and density   1
17	Basak, Subhasish	basak@theory.saha.ernet.in	top
	S. Basak and Asit K. De
	Investigation of Gauge-fixed pure U(1) theory at strong coupling
	Gauge fixing has been very fruitful for abelian lattice chiral gauge theories. So far all the investigations in this theory have been done at relatively weak gauge coupling. Here, we numerically investigate the phase diagram of pure U(1) gauge theory at strong gauge coupling. The FM-FMD phase transition, which proved useful in defining a chiral gauge theory, seems to persist also at strong gauge coupling. However, evidence for confinement is weak.
	parallel talk	Chiral fermions and gauge theories   2
18	Beard, Bernard	bbbeard@cbu.edu	top
	B.B. Beard
	Scaling violations in the antiferromagnetic Heisenberg model
	We discuss finite-size scaling of the correlation length in the quantum antiferromagnetic Heisenberg model for various spin magnitudes S, measured with quantum Monte Carlo methods. As S gets larger, scaling violations at large values of \xi(L)/L disappear. This enables the reliable extrapolation of correlation length to astronomical values.
	parallel talk	Spin models   1
19	Becirevic, Damir	Damir.Becirevic@roma1.infn.it	top
	D.Becirevic, V.Gimenez, V.Lubicz, G.Martinelli, M.Papinutto
	Computing the matrix elements of the four-fermion operators with/without subtractions
	We present several new results obtained by using the SPQcdR proposal to compute the matrix elements of the 4-fermion operators by using the Wilson action and without encountering the problems of mixing with operators of the same naive dimension. An appropriate comparison with the results obtained by non-perturbatively computed renormalization and subtraction constants is also provided.
	parallel talk	Hadronic matrix elements   3
20	Belavin, Vladimir	belavin@mccme.ru	top
	V.A. Belavin, M.N. Chernodub, F.V. Gubarev, M.I. Polikarpov
	Numerical study of Frohlich and Marchetti monopole creation operator
	We perform the numerical study of the monopole creation operator recently suggested by Frohlich and Marchetti. Calculations in compact Abelian Higgs model and in the SU(2) lattice gauge theory in the Maximal Abelian projection show that monopoles are condenced in the confinement phase and are not condenced in the deconfinement phase.
	parallel talk	Topology and confinement   1
21	Beneke, Martin	mbeneke@physik.rwth-aachen.de	top
	Martin Beneke
	CP violation and the CKM matrix
	[plenary talk]
	plenary talk
22	Berg, Bernd	berg@hep.fsu.edu	top
	B.A.Berg, U. Heller, H. Markum, R. Pullirsch and W. Sakuler
	Zero modes of the Neuberger Dirac operator in 4d U(1) gauge theory
	We have calculated the low-lying eigenmodes of the Neuberger overlap-Dirac operator in 4d U(1) lattice gauge theory. In the strong coupling limit we find exact zero modes, similar as for non-Abelian gauge theories. Subsequently, we make an attempt to identify responsilbe topological exitations.
	parallel talk	Topology and confinement   3
23	BERNARD, Claude	cb@lump.wustl.edu	top
	The MILC collaboration (C. Bernard, T. Burch, S. Datta, T. DeGrand, C. DeTar, Steven Gottlieb, U.M. Heller, K. Orginos, R. Sugar, and D. Toussaint)
	Heavy-light decay constants with three dynamical flavors
	We present preliminary results for the heavy-light leptonic decay constants in the presence of three light dynamical flavors. We use an order $\alpha_s^2 a^2, a^4$ Symanzik improved gauge action and an order $\alpha_s a^2, a^4$ improved staggered action for the dynamical background configurations. These are then analyzed, in a "partially quenched" manner, with tadpole improved clover valence fermions using the Fermilab formalism. The three-flavor dynamical lattices include a wide range of dynamical quark masses and are matched in lattice spacing at $\approx 0.13$ fm. We have additional data with two flavors and with quenched lattices for comparison. We find a significant increase in $f_B$ with three dynamical flavors over the quenched case; there is also an increase, although not as significant, when we compare three-flavor to two-flavor results.
	poster	Heavy quark physics
24	Berruto, Federico	fberruto@bu.edu	top
	F. Berruto, L. Giusti, C. Hoelbling, C. Rebbi
	A Simulation of the 't Hooft Model at finite Nc with the Overlap Dirac Operator
	We present first results of a numerical simulation of the 't Hooft model, i.e. two dimensional QCD with Nc colors, based on the overlap action. We compute the masses of the low-lying mesonic states and the chiral condensates for U(Nc) and SU(Nc) (Nc=2,3,4) gauge groups. A comparison with the analytic results in the large Nc limit is discussed.
	parallel talk	Chiral fermions and gauge theories   2
25	Bertle, Roman	bertle@kph.tuwien.ac.at	top
	Roman Bertle, Manfried Faber, Jeff Greensite, Stefan Olejnik
	Vortices in the SU(2)-Higgs model
	A Higgs field in the fundamental representation is able to screen color-electric charges. In the vortex model the quark-antiquark potential can be understood via the linking between Wilson loops and vortex sheets. We investigate the influence of a massive fundamental Higgs-field on center vortices within SU(2) lattice gauge theory. The simulation for various couplings and temperatures shows, that with increasing coupling between the Higgs and the gauge field vortices become depercolated. In addition the dependence of the results on different methods to identify vortices is discussed.
	poster	Topology and confinement
26	Bhattacharya, Tanmoy	tanmoy@lanl.gov	top
	T. Bhattacharya, R. Gupta, W. Lee
	Nonperturbative Renormalization: Fixed gauge vs Ward Identities
	Calculations of renormalization constants with external quark states in a fixed gauge are computationally easier than those using Ward Identities, and can be used to determine the scale dependent constants as well. The theoretical uncertainties, however, in the fixed gauge method are not fully under control. In this talk, I shall compare our Ward identity results with those obtained from momentum scheme with external quark states in the Landau gauge.
	parallel talk	Improvement and renormalization   1
27	Bietenholz, Wolfgang	bietenho@physik.hu-berlin.de	top
	W. Bietenholz, N. Eicker, I. Hip, Th. Lippert, K. Schilling
	Fast Evaluation of Overlap Fermions
	Our ansatz to insert a truncated perfect hypercube fermion into the overlap formula is tested in quenched QCD on lattices of size L=4, 8 and 12. We observe a very significant accelaration of the convergence in the evaluation of the inverse square root, as well as an improved degree of locality compared to the standard overlap fermion.
	parallel talk	Improvement and renormalization   4
28	Bittner, Elmar	bittner@kph.tuwien.ac.at	top
	E. Bittner, W. Janke, H. Markum
	Spins Coupled to a $Z_2$-Regge Lattice in 4d
	We study an Ising spin system coupled to a fluctuating four-dimensional $Z_2$-Regge lattice and compare with the results of the four-dimensional Ising model on a regular lattice. Particular emphasis is placed on the phase transition of the spin system and the associated critical exponents. We present result from finite-size scaling analyses of extensive Monte Carlo simulations.
	poster	Quantum gravity and random surfaces
29	Blum, Tom	tblum@bnl.gov	top
	T. Blum (RBC Collaboration)
	${\rm Im} A_0$, ${\rm Im} A_2$ and $\epsilon^\prime$ from Quenched Lattice QCD
	We present results for the $CP$ violating imaginary parts of the isospin 0 and 2 amplitudes (Im$A_{0,2}$) describing $K\to\pi\pi$ decays in the Standard Model. Starting from the lattice values for the low energy constants of $K \rightarrow \pi\pi$ matrix elements, we discuss the operator matching to continuum normalizations and the perturbative Wilson coefficients which are needed to find the physical values for the matrix elements. Combining these with the real parts of the amplitudes, we estimate the value of the direct $CP$ violation parameter $\epsilon^\prime$ and discuss the approximations in this estimate. Our quenched calculation uses domain wall fermions with $L_s=16$ and the Wilson gauge action at $\beta=6.0$ on 16^3 x 32 lattices.
	parallel talk	Hadronic matrix elements   2
30	Blythe, Danielle	pydb@swan.ac.uk	top
	Danielle Blythe
	Functional form for lattice correlators at small times
	The analytic form of the lattice quark propagators are used to derive the functional form for short distance mesonic correlators. These are then used to calculate ``Continuum Model'' Ansatz\"e which are compared to Monte Carlo data.
	poster	QCD spectrum and quark masses
31	Bogolubsky, Igor	bogolubs@cv.jinr.ru	top
	I.L.Bogolubsky
	Hopf index extension and topological solitons in 3D Heisenberg lattice spin models
	An extension of the 'continuous' Hopf index is defined for essentialy discrete case - in 3D lattice Heisenberg spin models. A class of such models with competing interactions is considered (ferromagnetic with nearest neighbours, and antiferromagnetic with next-to-nearest neighbours). Stable localized spin configurations (lattice solitons) with unit lattice Hopf index are found which minimize the Hamiltonian of the spin system in the topological sector chosen.
	poster	Spin models
32	Borici, Artan	borici@ph.ed.ac.uk	top
	UKQCD Collaboration: A. Borici, B. Joo, A.D. Kennedy, B. Pendleton, U. Wenger
	The dynamical Ginsparg-Wilson fermions project
	Lattice QCD with Ginsparg-Wilson fermions is a well defined theory at non-zero lattice spacing and smooth gauge fields. The project aims to investigate the feasibility of carrying out realistic dynamical Ginsparg-Wilson fermion simulations and to find those parameters for which the theory is local.
	parallel talk	Chiral fermions and gauge theories   3
33	Bornyakov, Vitaly	vborn@ifh.de	top
	V.Bornyakov, G.Schierholz, T. Streuer
	'Glueball and gluelump spectrum in abelian projected QCD'
	We study glueball and gluelump spectra calculated after abelian projection in both quenched and N_f=2 full QCD. The abelian projection is made after MA gauge fixing. We demonstrate that both spectra can be recovered despite the problem with positivity. We suggest the interpretation of some of the gluelump states in the language of the abelian projected theory.
	parallel talk	Topology and confinement   7
34	Bornyakov, Vitaly	vborn@ifh.de	top
	V.Bornyakov and M.Mueller-Preussker
	Continuum limit in abelian projected SU(2) lattice gauge theory
	We study the continuum limit of the abelian string tension and the density of abelian monopoles calculated after fixing maximal abelian gauge. We employ the simulated annealing algorithm to fix the gauge. We present the evidence that the abelian string tension converges to the nonabelian one in the continuum limit. For the monopole density we confirm earlier findings that the density of monopoles in the properly defined largest cluster has correct scaling while the total density is divergent in the continuum limit due to ultraviolate contribution. We compare our results with results obtained with the usual iterative gauge fixing algorithm.
	poster	Topology and confinement
35	Bowman, Patrick	pbowman@csit.fsu.edu	top
	P.O. Bowman, U.M. Heller and A.G. Williams
	The Quark Propagator in Landau and Laplacian Gauges
	We study the lattice quark propagator in Landau gauge and Laplacian gauge, which is free of Gribov copies. We use two quark actions: the normal staggered (Kogut-Susskind) action and an improved staggered action, Asqtad. These actions are seen to provide good, clean signals and the effect of order a^2 improvement is clearly seen. The two gauges produce similar results.
	parallel talk	Improvement and renormalization   4
36	Boyle, Peter	paboyle@ph.ed.ac.uk	top
	Peter Boyle, Gunnar Bali
	The interquark potential in lattice perturbation theory to O(alpha^2).
	We calculate Wilson loops and derived quantities to O(alpha^2) in lattice perturbation theory. This includes the perturbative static potential and small Wilson loops to O(alpha^2), in the presence of massive dynamical Wilson, Clover and Kogut-Susskind quarks. The results may be used to understand the mass dependent effects of dynamical fermions on the potential, and to obtain the \overline{MS} coupling in a number of ways.
	parallel talk	Improvement and renormalization   3
37	Brower, Richard C.	brower@bu.edu	top
	Richard C. Brower
	Is the Graviton a Domain Wall Glueball?
	The AdS/CFT duality conjecture relates strings in higher dimensions to Yang-Mills theory. In particular supergravity excitations in an $AdS^7$ black hole are dual to glueballs states at strong coupling. Comparison of the full spin-parity structure with lattice calculations of the glueball spectrum by Morningstar and PeardDon reveals a remarkable similarity in spite of the limitations of the strong coupling approximation. Further by introducing a domain wall cut off in the UV, a new zero mass tensor state is found giving rise to Einstein Hilbert gravity, as well as a zero mass Kaluza-Klein photon and dilaton states, interacting with QCD glueballs. In this scenario, the "fundamental" superstring for gravity and QCD string for the confined phase are identical with the warped scale factor in the extra dimension accounting for mass hierarchy between $\Lambda_{QCD}$ and $M_{Planck}$. Although this brane world gravity models have not been rigorously constructed in string theory, it does suggest a novel interpretation worthy of consideration.
	parallel talk	Theoretical developments   2
38	Burch, Tommy	tburch@physics.arizona.edu	top
	Tommy Burch Kostas Orginos Doug Toussaint
	Determining hybrid content of heavy quarkonia using lattice NRQCD
	Using lowest-order lattice NRQCD to create heavy meson propagators and applying the spin-dependent interaction, $c_B^{} \frac{-g}{2m_q}\vec\sigma\cdot\vec{B}$, at varying intermediate time slices, we compute the off-diagonal matrix element of the Hamiltonian for the quarkonium-hybrid two-state system. Diagonalizing this two-state Hamiltonian, the admixture of hybrid ($|Q\bar{Q}g\rangle$) in the ground state is found. We present results from a set of quenched lattices with an interpolation in quark mass to match the bottomonium spectrum.
	parallel talk	Heavy quark physics   3
39	Campostrini, Massimo	Massimo.Campostrini@df.unipi.it	top
	Matteo Beccaria, Massimo Campostrini, Alessandra Feo
	Hamiltonian Monte Carlo simulation of the two-dimensional Wess-Zumino model
	We study a Hamiltonian lattice formulation of the two-dimensional N=1 Wess-Zumino model by means of Quantum Monte Carlo techniques. We analyze the performance of the algorithm and present preliminary results on the pattern of supersymmetry breaking.
	parallel talk	Higgs Yukawa SUSY theories   1
40	Capitani, Stefano	stefano@mitlns.mit.edu	top
	Stefano Capitani
	Perturbative renormalization for overlap fermions
	Using lattice overlap fermions, we have computed the 1-loop renormalization factors of several operators that measure DIS structure functions and weak amplitudes. Computer codes written in the algebraic manipulation language FORM have been used. The improvement of the operators is also discussed.
	parallel talk	Improvement and renormalization   4
41	Caracciolo, Sergio	sergio.caracciolo@sns.it	top
	Sergio Caracciolo, Andrea Pelissetto, Antonio Rago
	Two-loop propagator for Wilson fermions
	We have computed the propagator of the Wilson fermions at two loops in lattice QCD by evaluating Feynman integrals with the coordinate-space method. We can thus check a recent two-loop computation of the critical mass for Wilson fermions. We present the results for different types of infrared regularization. We confirm both the previous numerical estimates and the power of the coordinate space method whenever high accuracy is needed.
	poster	Improvement and renormalization
42	Caselle, Michele	caselle@to.infn.it	top
	M. Caselle, M. Hasenbusch, P.Provero and K. Zarembo
	Bound states in the 3d Ising model and implications for QCD at finite temperature and density
	We study the spectrum of bound states of the three dimensional Ising model in the (h,beta) plane near the critical point. In particular we concentrate on the value of the binding energy as we move around the critical point. Our results support the existence of two well defined phases. A first one, near the h=0 axis in the beta>beta_c regime, in which the binding energy is greater than zero and decreases as the magnetic field is increased and a second one, near the h=0 axis in the beta<beta_c regime in which the binding energy is zero. The two phases are separated by a line in the (h,beta) plane which lies near (and could even coincide with) the Kertesz line. This result has various interesting implications if we look at the three dimensional Ising model in a magnetic field as an effective theory for hot QCD in the (mu,T) plane. The bound states that we discuss can be easily identified with diquarks which appear in the colour superconductivity phase and the unbinding line that we detect can be mapped into the line which separates this phase from the quark gluon plasma one.
	parallel talk	Non-zero temperature and density   1
43	catterall, simon	smc@physics.syr.edu	top
	Simon Catterall
	Exact Lattice Supersymmetry
	We construct a lattice action for the two-dimensional Wess Zumino model with extended (N=2) supersymmetry and show that it retains a exact supersymmetry on the lattice. The presence of this invariance guarantees that the full supersymmetry is restored without fine tuning in the continuum limit. We present results from a dynamical fermion simulation which support these conclusions
	parallel talk	Higgs Yukawa SUSY theories   1
44	Cea, Paolo	Paolo.Cea@ba.infn.it	top
	P. Cea, M. Consoli, and L. Cosmai
	Dynamics of the scalar condensate in thermal four dimensional self-interacting scalar field theory on the lattice.
	We simulate the scalar self-interacting four dimensional field theory on the lattice at finite temperature. By varying the temperature we find that our scalar system undergoes a phase transition from the broken phase to the symmetric phase. Our data show that the zero-momentum wave-function renormalization increases by approaching the critical temperature. On the other hand, the finite-momentum wave-function renormalization remains remarkably constant.
	poster	Higgs Yukawa SUSY theories
45	Chandrasekharan, Shailesh	sch@phy.duke.edu	top
	S. Chandrasekharan
	Superconductivity and Chiral Symmetry Breaking using Fermion Clusters
	Recent progress suggests that it may be useful not to integrate out the fermions but to identify the relevant degrees of freedom in terms of fermionic clusters. We give two examples for this view point. We first discuss how superconductivity arises in a Hubbard Type Model in the language of fermionic clusters. This has resulted in the first precision study of a Kosterlitz-Thouless phase transition. We then discuss how chiral symmetry breaking arises in strongly coupled Lattice QCD in the language of fermion clusters.
	parallel talk	Theoretical developments   2
46	Chatelain, Christophe	chatelai@itp.uni-leipzig.de	top
	Christophe Chatelain, Bertrand Berche, Wolfhard Janke, Pierre Emmanuel Berche
	Evidence for softening of first-order transition in 3D by quenched disorder
	We study by extensive Monte Carlo simulations the effect of random bond dilution on the phase transition of the three-dimensional 4-state Potts model which is known to exhibit a strong first-order transition in the pure case. The phase diagram in the dilution-temperature plane is determined from the peaks of the susceptibility for sufficiently large system sizes. In the strongly disordered regime, numerical evidence for softening to a second-order transition induced by randomness is given. Here a large-scale finite-size scaling analysis, made difficult due to strong crossover effects presumably caused by the percolation fixed point, is performed.
	parallel talk	Spin models   1
47	Chernodub, Maxim	maxim@heron.itep.ru	top
	M.N.Chernodub, F.V.Gubarev, M.I.Polikarpov and V.I.Zakharov
	Heavy monopole potential in gluodynamics
	We discuss predictions for the interaction energy of the fundamental monopoles in gluodynamics introduced via the 't Hooft loop. We argue, in particular, that the dual gluon interacting with the magnetic charges can be considered as a U(1) gauge boson. We predict the intermonopole potential at short and large distances and at small and high temperatures. Our predictions are in qualitative agreement with the existing lattice data.
	parallel talk	Topology and confinement   1
48	Chiu, Ting-Wai	twchiu@phys.ntu.edu.tw	top
	Ting-Wai Chiu
	The index of a GW Dirac operator
	A novel feature of a Ginsparg-Wilson Dirac operator is discussed. Unlike the Dirac operator for massless fermions in the continuum, this GW Dirac operator does not possess exact zero modes for any topologically-nontrivial background gauge fields, even though it is local, doublers-free, and reproduces correct axial anomaly in topologically-trivial gauge backgrounds.
	parallel talk	Chiral fermions and gauge theories   1
49	Choe, Seungho	schoe@hiroh2.hepl.hiroshima-u.ac.jp	top
	O. Miyamura and S. Choe
	Chemical potential response of pseudoscalar meson masses in the Nambu--Jona-Lasinio model
	Using the Nambu--Jona-Lasinio (NJL) model we study the chemical potential response of the pion and kaon masses as a function of temperature and chemical potential, i.e., $dm/d\mu$ ($T$, $\mu$). First, we obtain the responses assuming that the vector--axial-vector coupling is zero ($g_V$ = 0). Then, we include a non-zero $g_V$, and study the effects of $g_V$ on the responses. We find that the behavior of $dm/d\mu$ for the pion is quite different from that for the kaon. It means that $dm/d\mu$ is much dependent on the mass difference between the two quarks, i.e., the $u$ and $s$ quarks, or even between the $u$ and $d$ quarks. Our results can give a clue for future studies of $dm/d\mu$ on the lattice.
	poster	Non-zero temperature and density
50	Christ, Norman	nhc@phys.columbia.edu	top
	Norman Christ
	Status of the QCDOC Project
	[QCD machine report]
	plenary talk
51	Christ, Norman	nhc@phys.columbia.edu	top
	Norman Christ and Lingling Wu
	The QCD Phase Transition with Domain Wall Fermions
	Earlier QCD thermodynamics studies on 8^3 x 4 and 16^3 x 4 volumes are enhanced with increased statistics and extended to a smaller lattice spacing using a 16^3x6 volume. A comparison between the results for four and six time slices suggests that the domain wall method provides a consistent description of finite temperature QCD. Added statistics give a more precise measurment of anomalous chiral symmetry breaking above the phase transition. We also provide an explicit comparsion with the smaller, non-anomalous chiral symmetry breaking effects present in the domain wall calculation. Explicit determination of the lowest Dirac eigenvalues gives further information about possible topological effects.
	parallel talk	Non-zero temperature and density   2
52	Christ, Norman	nhc@phys.columbia.edu	top
	Norman Christ
	Cost of dynamical quark simulations
	[Panel statement]
	plenary talk
53	Clowser, Jonathan	pyjc@swan.ac.uk	top
	J. Clowser
	Application of Maximum Entropy Method to Dynamical Fermions.
	MEM is applied to dynamical fermion simulations of the (2+1)D Nambu Jona-Lasinio model. This model is particular interesting because it has a phase where there is a resonance, and hence the simple pole assumption of traditional fitting procedures breaks down. Results for the spectral function of this model obtained from MEM will be shown.
	parallel talk	Non-zero temperature and density   4
54	Colangelo, Gilberto	gilberto@physik.unizh.ch	top
	Gilberto Colangelo
	Chiral perturbation theory, dispersion relations and final state interactions in K -> pi pi
	[plenary talk]
	plenary talk
55	collins, sara	collins@physics.gla.ac.uk	top
	S. Collins, C. Davies, G. Lepage, J. Shigemitsu
	A nonperturbative determination of c_A and the scaling of f_pi and renormalised quark mass
	We calculate the O(a) improvement coefficient for the axial-vector current using the nonperturbative method proposed by the LANL group. Results for the coefficient in the range beta=5.93 to 6.2 are presented. We find c_A is close to the 1-loop tadpole-improved perturbative value. In addition, scaling of the pseudoscalar decay constant and renormalised quark mass is improved compared to that obtained using the (larger) c_A values obtained by the ALPHA collaboration.
	parallel talk	Improvement and renormalization   1
56	Cosmai, Leonardo	Leonardo.Cosmai@ba.infn.it	top
	P. Cea and L. Cosmai
	External field dependence of the deconfinement temperature in SU(3).
	We study the vacuum dynamics of SU(3) lattice gauge theory at finite temperature. Using the lattice Schroedinger functional, the SU(3) vacuum is probed by means of an external constant Abelian chromomagnetic field. Our preliminary numerical data suggest that, by increasing the strength of the applied external field, the deconfinement temperature decreases towards zero. This means that strong enough chromomagnetic fields destroy the confinement of color.
	poster	Topology and confinement
57	Costas, Strouthos	pycs@swan.ac.uk	top
	S.J. Hands, J.B. Kogut and C.G. Strouthos
	The three-dimensional Gross-Neveu model with a U(1) chiral symmetry at non-zero temperature.
	We present results from numerical simulations of the (2+1)-dimensional Gross-Neveu model with a U(1) chiral symmetry and N=4 fermion species at non-zeto temperature. We provide evidence that there are two different chirally symmetric phases separated by a Berezinskii-Kosterlitz-Thouless transition and that the fermions acquire dynamical mass which remains non-zero even in the high temperature phase.
	parallel talk	Non-zero temperature and density   5
58	Creutz, Michael	creutz@bnl.gov	top
	Michael Creutz, Ivan Horvath, and Herbert Neuberger
	A new fermion Hamiltonian for lattice gauge theory
	We formulate a Hamiltonian vector-like lattice gauge theory using the overlap formula for the spatial fermionic part, $H_f$. We define a chiral charge, $Q_5$ which commutes with $H_f$, but not with the electric field term. There is an interesting relation between the chiral charge and the fermionic energy with consequences for chiral anomalies in the adiabatic limit on the gauge fields.
	poster	Chiral fermions and gauge theories
59	Cristian, Calin	cristian@phys.columbia.edu	top
	T. Blum, P. Chen, N. Christ, C. Cristian, C. Dawson, G. Fleming, R. Mawhinney, S. Ohta, G. Siegert, A. Soni, P. Varanas, M. Wingate, L. Wu, Y. Zhestkov
	${\rm Re} A_0$ and ${\rm Re} A_2$ from Quenched Lattice QCD
	We have used domain wall fermions to calculate $K \rightarrow \pi$ and $K \rightarrow 0$ matrix elements which can be used to determine the $\Delta I = 1/2$ rule for K decays in the Standard Model. Nonlinearities in the $\Delta I = 3/2$ matrix elements due to chiral logarithms are explored and the subtractions needed for the $\Delta I = 1/2$ matrix elements are discussed. Using renormalization factors calculated using non-perturbative renormalization then yields values for real $A_0$ and $A_2$. We present the details of our quenched $16^3 \times 32 \times 16$, $\beta = 6.0$, $M_5 = 1.8$ simulation, where a previous calculation showed that the finite $L_s$ chiral symmetry breaking effects are small ($m_{res} \approx 4 \rm MeV$).
	parallel talk	Hadronic matrix elements   2
60	Cucchieri, Attilio	attilio@if.sc.usp.br	top
	Attilio Cucchieri, Tereza Mendes and Daniel Zwanziger
	SU(2) Running Coupling Constant and Confinement in Minimal Coulomb and Landau Gauges
	We present a numerical study of the space-space and time-time components of the gluon propagator at equal time in the minimal Coulomb gauge, and of the gluon and ghost propagators in the minimal Landau gauge. This work allows a non-perturbative evaluation of the running coupling constant and a numerical check of Gribov's confinement scenarios for these two gauges. Simulations are done in pure SU(2) lattice gauge theory at beta = 2.2. We consider several lattice volumes in order to control finite-volume effects and extrapolate our results to infinite lattice volume.
	parallel talk	Topology and confinement   6
61	D'Elia, Massimo	delia@ge.infn.it	top
	J.M. Carmona, M. D'Elia, A. Di Giacomo, B. Lucini, G. Paffuti
	DUAL SUPERCONDUCTIVITY AND CHIRAL SYMMETRY IN FULL QCD
	A disorder parameter detecting dual superconductivity of the vacuum is measured across the chiral phase transition in full QCD with two flavours of dynamical staggered fermions. The observed behaviour is similar to the quenched case.
	parallel talk	Topology and confinement   1
62	Damgaard, Poul	poul.damgaard@cern.ch	top
	Poul Damgaard
	Microscopic Dirac operator spectra
	[plenary talk]
	plenary talk
63	Davies, Christine	c.davies@physics.gla.ac.uk	top
	C. Davies, S. Collins, G. Cowan, J. Hein, J. Shigemitsu
	f_b from A_k
	We discuss the extraction of f_B from moving B mesons and using the spatial axial current. The comparison to zero momentum temporal axial current calculations is a necessary check of lattice systematic errors. The optimal smearing for moving B mesons is described.
	parallel talk	Heavy quark physics   5
64	de Forcrand, Philippe	forcrand@itp.phys.ethz.ch	top
	Ph. de Forcrand and L. von Smekal
	't Hooft loops, electric flux sectors and confinement
	Center vortices are strong candidates as the effective degrees of freedom responsible for confinement in Yang-Mills theory. Their free energy can be studied in a gauge invariant manner by considering the 't Hooft loop. At finite temperature, the spatial 't Hooft loop shows an area law in the hot, deconfined phase, and a screened behaviour in the cold, confined phase. By considering multiple 't Hooft loops, one can construct the partition function of a given electric flux sector, which shows confinement of electric charges (quarks) below T_c. Universality relates the magnitudes of the string tension and the dual string tension in the two phases.
	parallel talk	Topology and confinement   6
65	DeGrand, Thomas	degrand@aurinko.colorado.edu	top
	T. DeGrand
	Understanding chiral symmetry breaking with the overlap action
	A chiral fermion action allows one to do very clean studies of chiral symmetry breaking in QCD. I will briefly describe how to compute with the overlap action (relatively) cheaply, and then turn to physics: Low modes of the Dirac operator show a ``lumped'' chiral density which peaks at the locations of instantons and anti-instantons. These modes dominate correlation functions at small quark mass in many channels. The picture qualitatively (and in some cases quantitatively) resembles an instanton liquid model.
	parallel talk	Topology and confinement   4
66	DI GIACOMO, ADRIANO	adriano.digiacomo@df.unipi.it	top
	A.DI GIACOMO , G.PAFFUTI
	CONFINEMENT AND MONOPOLE CONDENSATION:SOME PROPERTIES OF THE DISORDER PARAMETER
	It is explicitely demonstrated that the disorder parameter used in previous works to detect dual superconductivity of the confined phase of QCD is gauge invariant and does not contradict Elitsur theorem. Problems related to the definition of monopoles in SU(N) gauge theories are also discussed.
	parallel talk	Topology and confinement   1
67	Di Pierro, Massimo	mdp@fnal.gov	top
	Massimo Di Pierro
	FermiQCD. A toolkit for rapid development of parallel lattice QCD applications.
	FermiQCD is a collection of classes and algorithms, written in C++, for rapid development of robust and efficient parallel lattice QCD applications (with arbitrary lattice dimensions and gauge groups). FermiQCD is based on Matrix Distributed Processing therefore all the algorithms are automatically parallelized with MPI. FermiQCD incorporates Luescher's SSE2 optimizations for Pentium 4 for Wilson, Clover, Staggered and Asqtad Staggered fermionic actions.
	poster	Algorithms and machines
68	Di Pierro, Massimo	mdp@fnal.gov	top
	Massimo Di Pierro and Paul Mackenzie
	On the non-pertubative tuning of the O(a^2) improved Kogut-Susskind action
	We discuss the possibility of a non-perturbative tuning of the effective coefficients that appear in the O(a^2) improved action for Kogut-Susskind fermions. The mass splitting for the different pions is used as a measure of the symmetry breaking effects introduced by O(a^2) discretization errors.
	parallel talk	Improvement and renormalization   2
69	Diamantini, Maria Cristina	cristina.diamantinitrugenberger@cern.ch	top
	P.H. Damgaard, M.C. Diamantini, P. Hernandez and K. jansen
	Finite Size Scaling of Meson Propagators in Quenched Chiral Perturbation Theory
	We present some new results for meson propagators and the quark condensate at finite volume in the chiral symmetry restoration regime in quenched chiral perturbation theory.
	poster	Chiral fermions and gauge theories
70	DIMOPOULOS, PETROS	pdimop@central.ntua.gr	top
	P. DIMOPOULOS, K. FARAKOS, and S. NICOLIS
	MULTI-LAYER STRUCTURE IN THE STRONGLY COUPLED 5D ABELIAN HIGGS MODEL
	We explore the phase diagram of the five-dimensional anisotropic Abelian Higgs model by Monte Carlo simulations. In particular, we study the transition between the confining phase and the four dimensional layered Higgs phase. We find that, in a certain region of the lattice parameter space, this transition can be first order and that each layer moves into the Higgs phase independently of the others ( decoupling of layers). As the Higgs couplings vary, we find, using mean field techniques, that this transition may probably become second order.
	poster	Higgs Yukawa SUSY theories
71	Dittmann, Leander	lrd@tpi.uni-jena.de	top
	L. Dittmann, T. Heinzl, A. Wipf
	A lattice study of the Faddeev-Niemi effective action
	We derive an effective action for the low energy sector of SU(2) Yang-Mills theory in terms of a unit color vector field n. Our ansatz for the effective action includes all operators with O(3)-symmetry and maximally four n-fields and/or derivatives. The effective couplings are obtained via inverse Monte Carlo techniques starting from a thermalized SU(2) Yang-Mills ensemble.
	poster	Topology and confinement
72	Dong, Shao-Jing	super124@ukcc.uky.edu	top
	Shao-Jing Dong, T. Draper, Keh Fei Liu, University of Kentucky F. X. Lee, George Washington University and J. B. Zhang, University of Adlaide
	Pion Decay Constant, Z_A, and quark masses from Overlap Fermions
	We report our calculation of the pion decay constant $f_\pi$, the axial renormalization constant $Z_A$, and the quark masses from the overlap fermions. The calculation is done on a quenched lattice with a size of $20^4$ and $a=0.15fm$ using improved gauge action. The smallest pion mass we reach is at 203 +- 25 MeV.
	parallel talk	Hadronic matrix elements   4
73	Draper, Terrence	draper@pa.uky.edu	top
	Shao-Jing Dong (University of Kentucky), Terrence Draper (University of Kentucky), Ivan Horvath (University of Kentucky), Frank X. Lee (George Washington University), Keh-Fei Liu (University of Kentucky), and Jianbo Zhang (University of Adelaide)
	Quenched Chiral Behavior of Hadrons with Overlap Fermions
	We study the quenched chiral behavior of hadrons with the pseudoscalar mass as low as $\approx 200\,{\rm MeV}$. These include the spectrum, the zero mode contribution to the pion correlation function, the renormalized quark mass, and quenched chiral logs in the pion mass and pseudoscalar decay constant. We also look at the quenched artifacts in the $a_0$ and $N^*$ propagators. The calculation is done on a quenched lattice of size $20^4$ and $a = 0.157(3)\,{\rm fm}$ using overlap fermions and an improved gauge action.
	poster	QCD spectrum and quark masses
74	Dreher, Patrick	dreher@mit.edu	top
	P. Dreher, MIT W. Akers, J. Chen, Y. Chen, C. Watson, Jefferson Lab
	Development of Web-based Tools for Use in Hardware Clusters Doing Lattice Physics
	Jefferson Lab and MIT are developing a set of web-based tools within the Lattice Hadron Physics Collaboration to allow lattice QCD theorists to treat the computational facilities located at the two sites as a single meta-facility. The prototype Lattice Portal provides researchers the ability to submit jobs to the cluster, browse data caches, and transfer files between the two sites and between cache and off-line storage. The user can view the configuration of the PBS servers and to monitor both the status of all batch queues as well as the jobs in each queue. Work is starting on expanding the present system to include job submissions at the meta-facility level (shared queue), as well as enhanced policy-based data management capabilities.
	poster	Algorithms and machines
75	Duncan, Anthony	tony@dectony.phyast.pitt.edu	top
	A. Duncan, E.Eichten, J. Yoo
	Hadronic Correlators from All-point Quark Propagators
	A method for computing all-point to all-point quark propagators is applied to a variety of processes of physical interest in lattice QCD. The method allows, for example, efficient calculation of disconnected parts and full momentum-space 2 and 3 point functions. Examples discussed (using both quenched and dynamical configurations) include: extraction of chiral Lagrangian parameters from current correlators, the pion form factor, and the unquenched eta-prime.
	parallel talk	Algorithms and machines   2
76	Durr, Stephan	stephan.duerr@psi.ch	top
	Stephan Durr
	Topology and hadron correlators in the $N_f=2$ Schwinger model
	Whether the topological charge of the gauge background has an influence on typical hadron correlators is analyzed in the Schwinger model with 2 active flavours. To this end Pion correlators are determined on configurations with fixed topological charge. It turns out that whether topology matters depends on the numerical value of a specific function of the quark mass and the box volume which is in close analogy to the Leutwyler Smilga parameter in full QCD.
	parallel talk	Topics in gauge theories   1
77	Edwards, Robert	edwards@jlab.org	top
	Robert Edwards
	Topology and low-lying fermion modes
	[plenary talk]
	plenary talk
78	Eichten, Estia	eichten@mcs.com	top
	E. Eichten, A. Duncan and H. Thacker
	Unquenched Studies using the Truncated Determinant Algorithm
	A status report on full QCD studies using the Truncated Determinant Algorithm with two light quarks. The focus will be on string breaking and the masses of light hadrons. Studies at very light quark masses are included.
	parallel talk	Topology and confinement   5
79	Eicker, Norbert	eicker@theorie.physik.uni-wuppertal.de	top
	N. Eicker for the SESAM collaboration
	Light Quark Masses with $N_f=2$ Wilson fermions: an Update from SESAM/T$\chi$L
	We present new results on the mass of the light and strange quarks from SESAM/T$\chi$L. The results were obtained on lattice-volumes of $16^3\times 32$ and $24^3\times 40$ points, which allows to investigate finite-size effects. Since the SESAM/T$\chi$L ensembles with \beta=5.6 are now complemented by configurations with \beta=5.5, moreover, we are able to attempt the continuum extrapolation of the quark masses with standard Wilson fermions.
	parallel talk	QCD spectrum and quark masses   1
80	Ejiri, Shinji	S.Ejiri@swansea.ac.uk	top
	Shinji Ejiri
	Aspects of thermal phase transition of 2-flavor QCD with small chemical potential
	QCD at finite temperature with two flavours of staggered fermions are studied. We estimate the quark mass dependence and the chemical potential response of the critical temperature by applying the reweighting method to the fermionic part of the Boltzmann factor.
	poster	Non-zero temperature and density
81	Engelhardt, Michael	engelm@pion08.tphys.physik.uni-tuebingen.de	top
	M. Engelhardt, M. Faber, H. Reinhardt
	Center vortex model for the infrared sector of Yang-Mills theory
	A model for the infrared sector of Yang-Mills theory is presented, based on magnetic vortices represented by (closed) random surfaces. The random surfaces, governed by an action related to their curvature, are investigated using Monte Carlo methods on a hypercubic lattice. A low-temperature confining phase and a high-temperature deconfined phase are generated by this simple dynamics. After fixing the parameters of the model such as to reproduce the relation between the deconfinement temperature and the zero-temperature string tension found in lattice Yang-Mills theory, a surprisingly accurate prediction of the spatial string tension in the deconfined phase results. Furthermore, the Pontryagin index associated with the lattice random surfaces of the model is constructed. This allows to also predict the topological susceptibility; the result is compatible with measurements in lattice Yang-Mills theory. Thus, for the first time an effective model description of the infrared sector emerges which simultaneously and consistently reproduces both confinement and the topological aspects of Yang-Mills theory within a unified framework.
	parallel talk	Topology and confinement   2
82	Faber, Manfried	bertle@kph.tuwien.ac.at	top
	Roman Bertle, Michael Engelhardt, Manfried Faber
	Topological Susceptibility of Monte-Carlo Generated Projected Vortices
	We identify thin center vortices in Monte-Carlo generated $SU(2)$ lattice Yang-Mills configurations using maximal center gauge and center projection. The topological susceptibility carried by these vortices is measured. In order to eliminate ultraviolet fluctuations two different smoothing procedures are applied before performing the measurements. The susceptibilities resulting from both methods are compatible with the one obtained from the full unprojected configurations by conventional methods.
	parallel talk	Topology and confinement   2
83	Farchioni, Federico	farchion@mail.desy.de	top
	F. Farchioni, A. Feo, R. Kirchner, T. Galla, C. Gebert, I. Montvay, G. M\"unster, A. Vladikas.
	The supersymmetric Ward identities on the lattice
	We present further results concerning the study of the lattice SUSY Ward Identities (WIs) in the N=1 SU(2) SUSY Yang-Mills theory (SYM). The study is part of a larger project in which SYM is simulated with Wilson fermions (gluinos) by the two-step multi-bosonic (TSMB) dynamical-fermion algorithm. We consider $\beta$=2.3 and $\kappa$=0.1925, 0.194, 0.1955, corresponding to a supposedly light gluino. As a result of the analysis of the WIs in the on-shell regime, we determine the ratio of the bare gluino mass $m_{\tilde{g}}$ with the coefficient multiplying the SUSY current in the lattice WIs, $Z_S=O(1)$, and the ratio of the coefficient of the mixing current $Z_T=O(g^2)$ with $Z_S$. The behavior of the determined ratios as a function of $\kappa$ is consistent with expectations, the first one allowing an estimate of the critical value by extrapolation to zero gluino mass.
	parallel talk	Higgs Yukawa SUSY theories   1
84	Feo, Alessandra	feo@uni-muenster.de	top
	F. Farchioni, A. Feo, T. Galla, C. Gebert, R. Kirchner, I. Montvay, G. M\"unster, R. Peetz.
	One-loop lattice perturbation theory of the supersymmetric Ward identities.
	We present preliminary results of a study of the SUSY Ward identities (WIs) for the $N=1$ $SU(2)$ SUSY Yang-Mills theory (SYM) in the context of one-loop perturbation theory on the lattice. The supersymmetry on the lattice is explicitly broken by the gluino mass and lattice artifacts. However, the renormalization of the local supercurrent can be carried out in a scheme that restores the nominal continuum WIs. The perturbative calculation of the renormalization constants and mixing coefficients for the local supercurrent is presented.
	parallel talk	Higgs Yukawa SUSY theories   1
85	Fiebig, H Rudolf	fiebig@fiu.edu	top
	H Rudolf Fiebig (for the LHPC)
	Spectral density calculations in a heavy-light meson-meson system
	A system of two static quarks, at fixed distances R, and two light quarks is studied on an anisotropic lattice. Excitations by operators emphasizing quark or gluon degrees of freedom are examined. The maximum entropy method is applied in the spectral analysis. These simulations ultimately aim at learning about mechanisms of hadronic interaction.
	parallel talk	Hadronic matrix elements   4
86	Fleming, George	gfleming@mps.ohio-state.edu	top
	George T. Fleming, Pavlos M. Vranas
	Staggered domain wall fermions, Part I
	We discuss the various reasonable approaches one might employ to include the spin diagonalization technique of staggered fermions within the domain wall framework. We will show that the choices of actions are quite restrictive if one intends to preserve all of the staggered lattice symmetries. We will also discuss the transfer matrix and the connection to the overlap formalism.
	parallel talk	Chiral fermions and gauge theories   2
87	Fodor, Zoltan	fodor@poe.elte.hu	top
	Z. Fodor, S.D. Katz
	A new method to study lattice QCD at finite T and mu and the determination of the critical point on the phase diagram
	We propose a method --an overlap ensuring multi-parameter reweighting technique-- to study QCD at finite temperature and chemical potential. We apply this method and determine the T-mu phase diagram of QCD with n_f=2+1 dynamical staggered quarks with semi-realistic masses on L_t=4 lattices. Based on universal arguments, it is believed that a critical point exists on the T-mu plane, which we also locate by finite size scaling of the Lee-Yang zeros.
	parallel talk	Non-zero temperature and density   3
88	Fortunato, Santo	fortunat@physik.uni-bielefeld.de	top
	Santo Fortunato, Helmut Satz
	Cluster Percolation and Explicit Symmetry Breaking in Spin Models
	The introduction of an external field $H$ in the Hamiltonian of a classical spin model breaks explicitly the global rotational symmetry enjoyed by the model when $H=0$. Because of that the model does not exhibit critical behaviour in the conventional sense, although it shows a number of interesting "pseudocritical" features. We investigate the relationship between such features and the percolation properties of the clusters which reproduce the critical behaviour of the model when $H=0$. We performed two different series of studies according to the order of the phase transition for $H=0$. For a second order phase transition we studied, by means of Monte Carlo simulations, the relationship between the Kert\'esz line and the `pseudocritical' line. Our comparison, performed on the 2D Ising model and on the 3D O(2) model at very small values of the external field, shows that the line of percolation critical points has the same functional form, a simple power law with exponent 1/(\beta\delta), as the pseudocritical line. For a first order phase transition we investigated the 3D 3-state Potts model: we find that along the line of first order phase transitions of the model the percolation strength of the standard Fortuin-Kasteleyn clusters makes a jump from zero to a non-zero value at the critical threshold. Exactly at the endpoint the percolation transition becomes continuous.
	parallel talk	Spin models   1
89	Fosco, Cesar	fosco@cab.cnea.gov.ar	top
	C. D. Fosco and A. López
	Generalized parity transformations in the lattice Chern-Simons theory
	We consider renormalization effects in the Abelian Chern-Simons (CS) theory. We show that those effects change the classical (odd) behaviour of the pure CS action under parity, and discuss them explicitly for the case of a lattice regularization. We also present results for the theory defined in the continuum, and explore the physical consequences of this anomaly. We also show that generalized, non local parity transformations can be defined in such a way that the regularized theory is odd, and that those transformations play an analogous role to the modified chiral symmetry of Ginsparg-Wilson fermions.
	parallel talk	Theoretical developments   1
90	Frezzotti, Roberto	Roberto.Frezzotti@mib.infn.it	top
	M. Della Morte, R. Frezzotti, J. Heitger
	Quenched twisted mass QCD at small quark masses and in large volume
	Lattice twisted mass QCD (tmQCD) with Wilson quarks is an ultraviolet regularization of QCD with two mass degenerate flavours. This lattice regularization is free from spurious fermion zero modes and is hence expected to be very convenient for pushing non-perturbative studies of QCD further towards the chiral limit. To check this expectation, we have performed extensive quenched simulations of lattice tmQCD with a lattice cutoff 1/a of about 2 and 2.8 GeV. The quark masses and the spatial lattice sizes (L) have been chosen such that M_pion/M_rho ranges from 0.65 to 0.47 and L*M_pion is about 5. We focused our attention onto the mass and the decay constant of the pseudoscalar and vector mesons, and set up the renormalization scheme so to directly compare (wherever possible) with results from standard quenched lattice QCD with Wilson quarks. Non-perturbative O(a) improvement has been implemented in both lattice formulations.
	poster	QCD spectrum and quark masses
91	Gadiyak, Valeriya	gadiyak@physics.umd.edu	top
	Valeriya Gadiyak Xiangdong Ji Chulwoo Jung
	Lattice Calculations of the Magnetic Moment and Electromagnetic Form Factors of the Nucleon.
	The internal structure of the nucleon is a very important problem for hadron physics as the hydrogen atom is for atomic physics. Despite many years of effort, theoretical understanding of the structure of the nucleon in terms of the fundamental degrees of freedom, quarks and gluons, remains elusive. Fortunately, for many years experiments have been performed to obtain information about nucleon structure. Useful probes of nucleon structure exist which direct couple to quarks and gluons. Understanding of this experimental information gives us check of the theory of strong interactions. Now it is one of the most important and challenging aspects of theoretical physics. One of the possible and useful probes of the nucleon structure is probe of the electromagnetic form factors and magnetic moments. The magnetic moments of the proton and neutron are known to very high precision from experiment. Lattice calculations of the moments could provide a useful check of the lattice simulations of the nucleon. There are two alternative ways to calculate the magnetic moment: first, extrapolation of the magnetic form factor G_M(Q^2) to Q^2=0, and second, using direct definition of the magnetic moment as an integral over [r x J]. Both methods should be investigated to fully understand errors. Purpose of our work is calculation of magnetic moment of nucleons using both methods and comparison with experiment. Systematic errors are also studied.
	parallel talk	Hadronic matrix elements   1
92	Garcia-Perez, Margarita	marga@mail.cern.ch	top
	QCD-TARO Collaboration
	Quenched charmonium near the continuum limit
	We study relativistic charmonium on a very fine quenched lattice (beta=6.6). We concentrate on the calculation of the hyperfine splitting of the J/psi and its dependence on the pseudoscalar mass. A systematic study of the effect of clover and tadpole improvement is presented. Results for the eta_c and J/psi wave functions will also be discussed.
	parallel talk	Heavy quark physics   2
93	Gattringer, Christof	christof.gattringer@physik.uni-regensburg.de	top
	C.Gattringer, M.Goeckeler, P.E.L. Rakow, S. Schaefer, A. Schaefer
	Topological excitations in finite temperature lattice QCD
	We analyze spectra of a chirally improved lattice Dirac operator, as well as locality and local chirality of its eigenvectors. We use quenched SU(3) gauge field configurations on both sides of the QCD phase transition. Our Dirac operator is an approximate solution of the Ginsparg-Wilson equation. Studying the finite volume behaviour of our observables and their scaling with beta we find evidence for the interpretation of the dominant excitations seen by the Dirac operator as a fluid of instanton-like objects.
	parallel talk	Topology and confinement   4
94	Gavai, Rajiv V.	gavai@tifr.res.in	top
	R. V. Gavai
	The Deconfinement Transition in SU(4) Lattice Gauge Theory
	The deconfinement transition in SU(4) lattice gauge theory is studied on $N_s^3 \times N_t$ lattices with $N_s$ = 8, 10, 12 and $N_t$ = 4 and 6 using a modified Wilson action which is expected to have no bulk transitions. The susceptibility $\chi_{|L|}^{\rm max}$ is found to increase {\it linearly} with spatial volume for $N_t$ = 4, indicating a first order deconfinement phase transition. However, the average action at the transition point shows a {\it non-gaussian} distribution and the corresponding $\chi^{\rm max}$, albeit very tiny, also increases linearly with volume.
	parallel talk	Non-zero temperature and density   4
95	Gebert, Claus	Claus.Gebert@desy.de	top
	F. Farchioni, C. Gebert, I. Montvay, L. Scorzato
	QCD spectroscopy with three light quarks
	The parameters of the low energy effective chiral Lagrangian can be determined by numerical simulations with three sufficently light quark flavours. Such Monte Carlo simulations can be performed with the two-step multi-bosonic (TSMB) algorithm which we previously used in supersymmetric Yang-Mills theory. We present first results concerning the applicability of this algorithm to QCD spectroscopy with three light quarks. The performance of its implementation on up-to-date supercomputers (Cray T3E, ApeMille) is investigated. Results from the tuning of the quark mass (by using its relation to the pseudoscalar mass) and the lattice spacing (by the Sommer scale $r_0$) as required for a reliable extraction of the Gasser-Leutwyler parameters are presented.
	parallel talk	QCD spectrum and quark masses   1
96	Gehrmann, Bernd	bernd@physik.hu-berlin.de	top
	Bernd Gehrmann, Juri Rolf, Stefan Kurth, Ulli Wolff
	Schrödinger functional at negative flavour number
	We study the Schrödinger functional coupling for lattice Yang-Mills theory coupled to an improved bonosic spinor field, which corresponds to QCD with minus two light flavours. This theory serves as a less costly testcase than QCD for the scaling of the coupling and the decoupling of heavy quarks.
	parallel talk	Improvement and renormalization   2
97	Gill, James	jfg@ph.ed.ac.uk	top
	J. Gill, ukqcd collaboration
	Semileptonic decay of a heavy light pseudoscalar to a light vector meson
	The form factors for the semileptonic decay of a heavy light pseudoscalar to a light vector meson are calculated in lattice QCD. The relativistic, noperturbatively improved action and quenched approximation are used. Results are presented for the case D_s -> phi and extrapolated to B -> rho.
	parallel talk	Heavy quark physics   4
98	Giusti, Leonardo	lgiusti@bu.edu	top
	L. Giusti, C. Hoelbling, C. Rebbi
	Preliminary results on the light quark masses with overlap fermions
	We present our first results for the light quark masses computed with the overlap action in the quenched approximation at beta=6.0 and V=16^3X32. The relevant renormalization constants are computed non-perturbatively in the RI scheme and matched to MSbar at the NNLO.
	parallel talk	Chiral fermions and gauge theories   3
99	Gliozzi, Ferdinando	gliozzi@to.infn.it	top
	Ferdinando Gliozzi, Antonio Rago
	String breaking mechanisms induced by magnetic and electric condensates
	In gauge theories coupled to matter there can be two different phases where the flux connecting external sources tends to form confining strings. The much more studied case is characterized by the condensation of magnetic monopoles. Sometimes one can find another phase with simultaneous condensation of magnetic and electric charges. In both phases the confining string breaks down at a given scale because of pair creation, however the mechanism is different. In the former case the string breaking is a mixing phenomenon which is invisible in the Wilson loops. As an example, in a 3D Z2 gauge-Higgs model we have verified that the Wilson loops obey a perfect area law even at distances larger than five times the string breaking scale. On the contrary in presence of both electric and magnetic condensates we argue that the string breaking is visible even in the Wilson loop, because the world-sheet of the string tears abruptly when the loop reaches a given size . A numerical experiment in a suitable region of the same 3D model neatly shows this dramatic phenomenon.
	parallel talk	Topology and confinement   5
100	Goeckeler, Meinulf	meinulf.goeckeler@physik.uni-regensburg.de	top
	M. Göckeler, R. Horsley, D. Pleiter, P.E.L. Rakow, S. Schaefer, A. Schäfer, G. Schierholz
	The spin structure of the Lambda hyperon in quenched lattice QCD
	It has been suggested to use the production of Lambda hyperons as a tool for investigating the nucleon spin structure. The viability of this idea depends crucially on the spin structure of the Lambda, for which several models are around. Using nonperturbatively O(a) improved Wilson fermions in the quenched approximation we have studied matrix elements of two-quark operators in the Lambda. In this talk, we shall present results for the axial vector current, which give us the contributions of the u, d, and s quarks to the Lambda spin.
	parallel talk	Hadronic matrix elements   1
101	Gottlieb, Steven	sg@indiana.edu	top
	Steven Gottlieb
	Cost of dynamical quark simulations
	[Panel statement]
	plenary talk
102	Gottlieb, Steven	sg@indiana.edu	top
	Steven Gottlieb (MILC Collaboration)
	Benchmarking and Tuning the MILC code on clusters and supercomputers
	During the past year we have benchmarked and tuned the MILC code on a number of architectures including Itanium, Pentium IV, dual CPU Athlon, the latest Alpha nodes (ES45). Results will be presented for many of these and we shall discuss some simple code changes that can result in very dramatic speedup of the KS conjugate gradient on processors with more advanced memory systems such as PIV, IBM SP and Alpha
	poster	Algorithms and machines
103	Gubarev, Fedor	gubarev@itep.ru	top
	F.V.Gubarev, V.I.Zakharov
	The Berry Phase and Monopoles in Gluodynamics
	The quantum mechanical geometrical (Berry) phase is considered in the context of SU(2) gluodynamics, both in the continuum and on the lattice. In the coherent state basis eigenvalues of every Wilson loop are naturally decomposed into geometrical and dynamical phase factors. Our approach allows in turn to define a gauge invariant monopole-like defects and study their properties on the lattice.
	parallel talk	Topology and confinement   1
104	Gupta, Rajan	rajan@lanl.gov	top
	T. Bhattacharya, R. Gupta, W. Lee, S. Sharpe
	Scaling behavior of improvement and renormalization constants
	I will summarize estimates of improvement and renormalization constants at beta=6.0, 6.2, 6.4 using O(a) improved clover action. An analysis of the scaling behavior of these constants will also be presented.
	parallel talk	Improvement and renormalization   2
105	Gupta, Sourendu	sgupta@tifr.res.in	top
	Rajiv Gavai, Sourendu Gupta and Robert Lacaze
	Quenched QCD at finite temperature with chiral Fermions
	We study physics at temperatures just above the QCD phase transition ($T_c$) using chiral (overlap) Fermions in the quenched approximation of lattice QCD. Exact zero modes of the overlap Dirac operator are localized and their frequency of occurrence drops with temperature. This is closely related to axial $U(1)$ symmetry, which remains broken upto $2\ T_c$. After subtracting the effects of these zero modes, chiral symmetry is restored, as indicated by the behaviour of the chiral condensate ($\ppbar$), and the ``pion'' and ``rho'' screening correlators are compatible with the corresponding ideal gas results.
	parallel talk	Non-zero temperature and density   2
106	Guralnik, Gerald	gerry@het.brown.edu	top
	R. Easther, P. Emirdag, G.S. Guralnik, S. Hahn and D. Petrov
	New approaches to Numerical Quantum Field Theory
	We outline the basis of two new methods particularly well suited to the analysis of phase structure in quantum field theory. The first method, "Source Galerkin", works on the continuum and, but for commutation properties, treats fermions and bosons in an equivalent manner. As a consequence, the traditional problems of Monte Carlo methods applied to fermionic fields, multiple poles and the fermion determinant, do not appear. Variants of algorithms developed for this method have been applied to perturbation theory and yield extremely accurate results with little computational time when compared to a Monte Carlo evaluation of the same integral. The second method, "Saddle Point Monte Carlo", can be loosely related to Source Galerkin and allows Monte Carlo techniques to be applied to actions which are not positive definite or even real.
	parallel talk	Theoretical developments   2
107	Gürtler, Martin	m.guertler@physics.gla.ac.uk	top
	Martin Gürtler, Christine Davies, Joachim Hein, G. Peter Lepage, Junko Shigemitsu
	Constrained curve fitting for three-point functions
	We analyze two- and three-point functions from quenched NRQCD to describe semileptonic B -> D decays. We illustrate the merits of constrained curve fitting.
	parallel talk	Heavy quark physics   5
108	Hagura, Hiroyuki	hagura@post.kek.jp	top
	H. Hagura
	Quantum geometry in dynamical Regge calculus
	We study the geomrtric properties of the higher-dimensional dynamical Regge calculus (DRC), which has been proposed as a hybridization of the dynamical triangulation (DT) and the Regge calculus (RC). In the strong coupling phase, entropy dominance makes the DRC similar to the DT. In the weak coupling phase, on the other hand, space-time becomes spiky configuration which often appears in the RC. We also discuss the possibility that lattice diffeomorphisms realized in the DRC might give a simple explanation for the Bekenstein-Hawking entropy from a viewpoint of simplicial gravity.
	parallel talk	Quantum gravity and random surfaces   2
109	Hands, Simon	s.hands@swansea.ac.uk	top
	Simon Hands
	QCD at non-zero T and mu
	[plenary talk]
	plenary talk
110	Harada, Junpei	harada@theo.phys.sci.hiroshima-u.ac.jp	top
	Junpei Harada, Shoji Hashimoto, Ken-Ichi Ishikawa, Andreas S. Kronfeld, Tetsuya Onogi, Norikazu Yamada
	One-loop renormalization of heavy-light currents
	We calculate the renormalization factors of heavy-light bilinears at one-loop order of perturbation theory, when the heavy quark is treated with the Fermilab formalism. We obtain the analytic result for the Feynman integrand for the (asymmetric) Fermilab action and the standard plaquette gauge action. We present numerical results for the Wilson and Sheikholeslami-Wohlert actions, with and without tree-level rotation. We find that in both cases our results smoothly interpolate from the static limit to the massless limit. This results are useful for B (D) meson decay constants and for form factors in semi-leptonic B (D) decay.
	parallel talk	Improvement and renormalization   3
111	Hart, Alistair	a.g.hart@damtp.cam.ac.uk	top
	A. Hart
	Topology and the scalar glueball with Nf=2 improved Wilson fermions.
	We measure the topological susceptibility and local topological properties on dynamical configurations over a range of sea quark masses at lattice spacings around 0.1 fm. We use a variety of gluonic methods and compare with the quenched theory on similar lattices. We also measure the `glueball' masses, and find the scalar mass to be suppressed relative to the quenched value on similar lattices.
	parallel talk	Topology and confinement   6
112	Hasenbusch, Martin	martin.hasenbusch@desy.de	top
	Martin Hasenbusch
	Speeding up the HMC
	We propose a modification of the Hybrid-Monte-Carlo method that allows for a larger step-size of the integration scheme at constant acceptance rate. The key ingredient is that the pseudo-fermion action is split into two parts. We test our proposal at the example of the two-dimensional lattice Schwinger model with two degenerate flavours of Wilson-fermions.
	parallel talk	Algorithms and machines   3
113	Hasenfratz, Anna	anna@eotvos.colorado.edu	top
	Anna Hasenfratz and Francesco Knechtli
	The Phase Diagram of QCD with Two and Four Flavors: Results with HYP Fermions
	The finite temperature phase transition of QCD is a chiral transition. It is directly connected to the topological structure of the vacuum and can strongly depend on the number of light quark flavors. In order to study thermodynamics on the lattice one needs a fermionic action with good chiral properties. We present simulation results obtained with the recently developed hypercubic blocked staggered action both with two and four flavors. With four flavors we find no sign of a first order phase transition and the mass dependence of the chiral condensate suggests that the zero mass phase transition occurs at very low temperature, if it exists at all.
	parallel talk	Non-zero temperature and density   2
114	Hasenfratz, Peter	hasenfra@itp.unibe.ch	top
	Peter Hasenfratz
	Conference summary
	[plenary talk]
	plenary talk
115	Hashimoto, Shoji	shoji.hashimoto@kek.jp	top
	JLQCD collaboration: S. Aoki, R. Burkhalter, M. Fukugita, S. Hashimoto, K.-I. Ishikawa, N. Ishizuka, Y. Iwasaki, K. Kanaya, T. Kaneko, Y. Kuramashi, M. Okawa, T. Onogi, S. Tominaga, N. Tsutsui, A. Ukawa, N. Yamada, T. Yoshie
	Exploration of sea quark effects in two-flavor QCD with the O(a)-improved Wilson quark action
	We carried out dynamical QCD simulations with nonperturbatively O(a)-improved Wilson fermions at beta=5.2. Finite-size effects are studied by using three different volumes 12^3x48, 16^3x48, and 20^3x48. Comparing the results with quenched data, we investigate sea quark effects in light hadron masses.
	parallel talk	QCD spectrum and quark masses   2
116	Hauswirth, Simon	hauswirt@itp.unibe.ch	top
	P. Hasenfratz, S. Hauswirth, K. Holland, T. Jorg, F. Niedermayer
	First results from a parametrized Fixed-Point QCD action
	We have constructed a new fermion action which is an approximation to the (chirally symmetric) Fixed-Point action, containing the full Clifford algebra with couplings inside a hypercube and paths built from renormalization group inspired fat links. We present exploratory studies of the light hadron spectrum, the energy-momentum dispersion relation and the deviation from the Ginsparg-Wilson relation.
	parallel talk	Improvement and renormalization   2
117	Haymaker, Richard	haymaker@rouge.phys.lsu.edu	top
	Andrei Alexandru and Richard W. Haymaker
	Connections between Tomboulis vortices and projection vortices
	We will present further connections between gauge invariant Tomboulis vortex counters and projection vortex counters. We will also present a simplified algorithm for identifying Tomboulis vortics. Finally some limited numerical comparisons between these approaches will be given.
	parallel talk	Topology and confinement   7
118	Hein, Joachim	jhein@ph.ed.ac.uk	top
	Joachim Hein, G. Peter Lepage, Quentin Mason
	Mass renormalisation for improved staggered quarks
	The mass renormalisation to O(alpha) of improved staggered quarks is shown to be well behaved. This is in contrast to naive staggered quarks, which suffer from large renormalisations as a consequence of unphysical flavour-changing strong interactions. Improved staggered quarks successfully suppress such interactions.
	parallel talk	QCD spectrum and quark masses   3
119	Heitger, Jochen	heitger@uni-muenster.de	top
	Jochen Heitger, Hubert Simma, Rainer Sommer, Ulli Wolff
	The Schrödinger functional coupling in quenched QCD at low energies
	The existing non-perturbative computation of the running coupling of quenched QCD in the Schrödinger functional scheme is extended to values of the scale mu=1/L (with L being the linear size of the finite system) that lie much deeper in the low energy regime than those considered before. By use of a modified sampling procedure to overcome long-time autocorrelations encountered in the numerical simulations at large couplings we are able to reach 1/mu ~ 0.9 fm, where a significant deviation from the perturbative evolution of the coupling is now demonstrated convincingly. Then also a comparison of its L-dependence in this region with a prediction from the strong coupling expansion can be attempted.
	poster	Improvement and renormalization
120	Heller, Urs M.	heller@csit.fsu.edu	top
	The MILC collaboration (C. Bernard, T. Burch, S. Datta, T. DeGrand, C. DeTar, Steven Gottlieb, U.M. Heller, K. Orginos, R. Sugar, and D. Toussaint)
	Thermodynamics with 3 and 2+1 Flavors of Improved Staggered Quarks
	We present preliminary results from exploring the phase diagram of finite temperature QCD with three degenerate flavors and with two light flavors and the mass of the third held approximately at the strange quark mass. We use an order $\alpha_s^2 a^2, a^4$ Symanzik improved gauge action and an order $\alpha_s a^2, a^4$ improved staggered action. The improved staggered action leads to a dispersion relation with diminished lattice artifacts, and hence better thermodynamic properties. It decreases the flavor symmetry breaking of staggered quarks substantially, and we estimate that at the transition temperature for an $N_t=8$ to $N_t=10$ lattice {\em all} pions will be lighter than the lightest kaon. Preliminary results on lattices with $N_t=4$, 6 and 8 are presented.
	parallel talk	Non-zero temperature and density   2
121	Hellmund, Meik	Meik.Hellmund@itp.uni-leipzig.de	top
	Meik Hellmund, Wolfhard Janke
	High temperature series expansions for $d$-dimensional disordered Potts models
	Despite considerable efforts there are still many open problems in the physics of disordered systems. One alternative to large-scale numerical simulations are systematic series expansions. Such expansions for statistical models defined on a lattice are a well-known method to study phase transitions and critical phenomena. The extension of this method to disordered systems demands the development of new graph theoretical and algebraic algorithms. We developed further the method of ``star graph expansion'' which allows to take the disorder average on the level of individual graphs. For the first time, we classified all star graphs up to order 19 and calculated their embedding numbers for $d$-dimensional hypercubic lattices. These data are used to calculate e.g. free energies and susceptibilities for disordered $q$-state Potts models on $d$-dimensional hypercubic lattices. The probability distribution of couplings is parameterized by e.g. $P(J_{ij}) = p ?d(J_{ij}-J_0) + (1-p) ?d(J_{ij}-R J_0)$ which includes spin glasses, diluted ferromagnets, random-bond models and transitions between them. The series allow the determination of the phase diagram, critical couplings and critical exponents in a large region of the ($q$,$d$,$p$,$R$) parameter space.
	poster	Spin models
122	Hepburn, Derek	derek@ph.ed.ac.uk	top
	Derek Hepburn
	Light hadron spectrum using an O(a)-Improved action with Nf=2
	We present recent light hadron spectrum results from the UKQCD collaboration. The analysis was performed on datasets generated using a non-perturbatively O(a)-Improved Wilson action with Nf=2 dynamical fermions.
	poster	QCD spectrum and quark masses
123	Herdoiza, Gregorio	gregorio.herdoiza@th.u-psud.fr	top
	A. Abada, Ph. Boucaud, G. Herdoiza, J.P. Leroy, J. Micheli, O. Pene, J. Rodriguez-Quintero
	A partonic signal on the lattice?
	We present the first attempt of a new method to compute the pion light-cone wave functions (LCWF) on the lattice. We compute the matrix element between the pion and the vacuum of a non-local operator: the propagator of a scalar quark (squark). A theoretical analysis shows the kinematical conditions for which the matrix element depends dominantly on the LCWF. We show some indications that for a short time the system of the spectator quark and the squark behave like partons, before they form a hadron-like bound state. This time is the place where the partonic wave function has to be looked for.
	parallel talk	Hadronic matrix elements   4
124	hernandez, pilar	pilar.hernandez@cern.ch	top
	pilar hernandez
	Ginsparg-Wilson fermions: practical aspects and applications
	[plenary talk]
	plenary talk
125	Hip, Ivan	hip@theorie.physik.uni-wuppertal.de	top
	I. Hip, Th. Lippert, H. Neff, K. Schilling, W. Schroers
	The Consequences of Non-normality
	Wilson-Dirac type operators (or any approximate Ginsparg-Wilson operators) are non-normal, i.e. they do not commute with their hermitian conjugates. This fact has some peculiar consequences. Non-normal operators were also considered in solid state physics. Numerical mathematicians recently introduced new concepts for their analysis. Are there lessons to be learnt for the lattice community?
	parallel talk	Theoretical developments   1
126	Hoelbling, Christian	hch@bu.edu	top
	L. Giusti, C. Hoelbling, C. Rebbi
	Quenched QCD with overlap fermions: numerical implementation and non-perturbative renormalization.
	We illustrate a numerical implementation of overlap fermions in quenched QCD and present preliminary results on the non-perturbative renormalization of fermionic bilinears. We study systems of size 10^3x20 and 16^3x32 at beta=6.0. Our results are in very good agreement with the scaling behavior predicted by perturbation theory to NNLO.
	parallel talk	Chiral fermions and gauge theories   3
127	Hoffmann, Roland	Roland.Hoffmann@Colorado.edu	top
	A. Hasenfratz, R. Hoffmann, F. Knechtli
	The Static Potential with Hypercubic Blocking
	We measure the static potential from Wilson loops constructed using hypercubic blocked (HYP) links. The HYP smearing mixes gauge links within hypercubes attached to the original link only. The HYP potential agrees with the potential measured using thin links for distances r/a>=2. We calculated the lowest order perturbative expansion of the lattice Coulomb potential of HYP links. These results are used in analyzing the static potential both on quenched and dynamical lattices. The statistical accuracy of the potential with HYP links improves by about an order of magnitude, which makes it possible to determine a reliable scale even with limited statistics.
	poster	Heavy quark physics
128	Hofheinz, Frank	hofheinz@physik.hu-berlin.de	top
	Frank Hofheinz Axel Thimm
	Perfect Actions: Insights in the Lattice Fermion Problem
	A revamping of the standard renormalization group approaches leads to an explicit expression of lattice formulations for arbitrary bilinear fermion actions, which can be further exploited to define new improvement methods or even chiral gauge theories The corresponding lattice fermion operators, satisfy a general Ginsparg Wilson relation. Here we present the formalism and a simple example in d=2.
	parallel talk	Chiral fermions and gauge theories   2
129	Holland, Kieran	holland@itp.unibe.ch	top
	P. Hasenfratz, S. Hauswirth, K. Holland, T. Joerg, F. Niedermayer
	Overlap construction with the parametrized Fixed-Point Dirac operator
	We examine the construction of an Overlap operator generated from D_FP. We look at the convergence of polynomial approximations of the inverse square root and the locality of the resulting operator. We investigate chiral properties of the spectrum and the eigenfunctions.
	poster	Chiral fermions and gauge theories
130	Holtmann, Sven	holtmann@physik.uni-bielefeld.de	top
	J. Engels, S. Holtmann, T. Schulze
	Specific heat and energy of the 3d O(2) spin model
	We investigate the three-dimensional $O(2)$ model on lattices of size $8^3$ to $120^3$ close to the critical point at zero magnetic field. We confirm explicitly the value of the critical coupling found by Ballesteros et al.. At criticality we study the finite-size dependencies of the energy $E$ and the specific heat $C$. We find that the size $C_{ns}$ of the nonsingular part of the specific heat is heavily dependent on the critical exponent $\alpha$ (or $\nu$). From the critical behaviour of the specific heat results on the largest lattices we determine the universal amplitude ratio $A^+/A^-$. The ratio varies linearly with the exponent $\alpha$ at small values of $\alpha$, well in accord with the relation $A^+/A^- \simeq 1-4\alpha$. Our best value for $\nu$ is $0.671(2)$ which amounts to $\alpha=-0.013(6)$.
	parallel talk	Spin models   1
131	Horata, Shinichi	horata@post.kek.jp	top
	H.S.Egawa, S.Horata and T.Yukawa
	Clear Evidence of a Continuum Theory of 4D Euclidean Simplicial Quantum Gravity
	4D simplicial quantum gravity coupled to both scalar and gauge fields has been studied using Monte-Carlo simulations. By adding the matter fields, we find the fact that the distinct three type phase structure exists with the contribution of the matter fields. We estimate a ratio of the number of scalar fields to that of gauge fields. As a result, the numerical results suggest that 4D simplicial manifold is related to the conformal symmetry in four dimensions. Furthermore, we observe the structure of the geometry with $S^4$ topology. Therefore, we propose a phase structure in detail with adding both scalar and gauge fields and discuss the possibility and the property of a continuum theory of 4D Euclidean simplicial quantum gravity.
	parallel talk	Quantum gravity and random surfaces   1
132	Horsley, Roger	roger@physik.hu-berlin.de	top
	R. Horsley
	A lattice determination of nucleon structure functions
	Using non-perturbatively O(a) improved Wilson fermions, results are given for the three lowest moments of the unpolarised nucleon structure functions. Renormalisation, chiral extrapolation and the continuum limit of the matrix elements are discussed. The simulations are performed for both the quenched theory and two flavours of unquenched fermions. A comparison between these results gives an impression of possible quenching effects.
	parallel talk	Hadronic matrix elements   1
133	Horvath, Ivan	horvath@pa.uky.edu	top
	Shao-Jing Dong, Terry Draper, Ivan Horvath, Frank Lee, Keh-Fei Liu, John McCune, Hank Thacker, Jianbo Zhang
	Lattice Fermions and the Vacuum of Pure Gauge QCD
	We investigate the vacuum properties of pure gauge QCD using fermionic methods. We concentrate on the utility of overlap fermions for this purpose, but also discuss the advantages and disadvantages of ultralocal formulations, mainly Wilson fermions.
	parallel talk	Topology and confinement   4
134	Ichie, Hiroko	ichie@physik.hu-berlin.de	top
	H.Ichie, V.Bornyakov, T.Streuer and G.Schierholz
	Comparison of the abelian flux tube in quenched and full QCD
	We have investigated the abelian flux-tube after fixing the maximally abelian gauge in full QCD. We found abelian flux-tube in the full QCD is very much the same as in quenched QCD up to the distance 2fm.
	poster	Topology and confinement
135	Ide, Kiyotomo	ide@het.ph.tsukuba.ac.jp	top
	CP-PACS Collaboration : S.~Aoki, R.~Burkhalter, M.~Fukugita, S.~Hashimoto, K.~Ide, N.~Ishizuka, Y.~Iwasaki, K.~Kanaya, T.~Kaneko, Y.~Kuramashi, V.~Lesk, M.~Okawa, Y.~Taniguchi, A.~Ukawa, T.~Yoshi\'e
	Non-perturbative renormalization for a renormarization group improved gauge action
	Renormalization constants of both vector and axial-vector currents are determined non-perturbatively in the quenched approximation for a combiation of a renormalization group improved gauge action and a tadpole-improved clover quark action using the Schr\"odinger functional method. Parameters of our calculation are chosen to be the same as those employed by a recent CP-PACS spectrum simulation. We find that non-perturbative values of renormalization constants differ from perturbative ones by about 6\% for vector current and 3\% for axial-vector current at the largest coupling of the CP-PACS simulation, $\beta$=2.575. We argue how scaling violation of meson decay constants observed is improved when our non-perturbative estimates of renormalization constants are used instead of perturbative ones.
	parallel talk	Improvement and renormalization   1
136	Ilgenfritz, Ernst-Michael	ilgen@rcnp.osaka-u.ac.jp	top
	K. Langfeld, E.-M. Ilgenfritz, H. Reinhardt, A. Sch\"afke Institut f\"ur Theoretische Physik, Universit\"at T\"ubingen
	Singular Gauge Potentials and the Gluon Condensate at Zero Temperature
	For $SU(2)$ gluodynamics, we consider a cooling procedure which separates $SO(3)$ gluon fields from singular center vortices. Contrary to the bulk of $P$-vortices, this ``vortex texture'' does not contribute to the string tension but it reproduces the lowest glueball states. Having a density scaling like $a^4$ with $\beta$, it gives a finite contribution to the action and energy density at $T=0$ in the continuum limit. We propose an interpretation of the action density as a mass dimension 4 condensate related to the gluon condensate. The different behavior of the condensate in the the positive plaquette model is discussed. We speculate about the continuum limit of these singular defects.
	poster	Topology and confinement
137	Ishibashi, Masato	ishibash@hep-th.phys.s.u-tokyo.ac.jp	top
	Kazuo Fujikawa and Masato Ishibashi
	Properties of a New Class of Lattice Dirac Operators
	A new class of lattice Dirac operators $D$ have been recently proposed on the basis of the generalized Ginsparg-Wilson relation, $\gamma_{5}(\gamma_{5}D) + (\gamma_{5}D)\gamma_{5} = 2a^{2k+1}(\gamma_{5}D)^{2k+2}$, where $k$ is a non-negative integer. We discuss the index theorem and locality properties for this general class of lattice Dirac operators.
	parallel talk	Chiral fermions and gauge theories   1
138	Ishii, Noriyoshi	ishii@th.phys.titech.ac.jp	top
	Noriyoshi Ishii, Hideo Suganuma, Hideo Matsufuru
	Glueball properties at finite temperature
	We study the glueballs properties at finite temperature using SU(3) lattice QCD at the quenched level with the anisotropic lattice. We present our results which shows the slight reduction of the scalar glueball mass near T_c.
	parallel talk	Non-zero temperature and density   6
139	Ishikawa, Ken-Ichi	kishika@suchi.kek.jp	top
	JLQCD collaboration: S. Aoki, R. Burkhalter, M. Fukugita, S. Hashimoto, K-I. Ishikawa, N. Ishizuka, Y. Iwasaki, K. Kanaya, T. Kaneko, Y. Kuramashi, M. Okawa, T. Onogi, S. Tominaga, N. Tsutsui, A. Ukawa, N. Yamada, T.~Yoshi\'{e}
	An exact algorithm for three-flavor QCD with $O(a)$-improved Wilson fermions
	We developed an exact simulation algorithm for the $O(a)$-improved Wilson fermion with odd number of flavors. The algorithm uses the non-Hermitian polynomials to approximate the inverse of the Dirac operator. The systematic errors caused by the polynomial approximation of the inverse is removed by the noisy-Metropolis test previously introduced in the multi boson algorithm.
	parallel talk	Algorithms and machines   3
140	Ishizuka, Naruhito	ishizuka@het.ph.tsukuba.ac.jp	top
	CP-PACS collaboration: S. Aoki, R. Burkhalter, M. Fukugita, S. Hashimoto, N. Ishizuka(*), Y. Iwasaki, K. Kanaya, T. Kaneko, Y. Kuramashi, V. Lesk, M. Okawa, Y. Taniguchi, A. Ukawa, T. Yoshie
	I=2 Pion Scattering Length and Phase Shift with Wilson Fermions
	We present preliminary results of scattering length and phase shift for I=2 Pion systyem calculated with the Wilson fermions in the quenched approximation. The finite size method presented by L\''uscher is employed, and the magnitude of finte size corrections are examined. The possibility of a calculation of K -> PiPi decay amplitudes with non-zero momentum pions on the lattice is also discussed.
	parallel talk	QCD spectrum and quark masses   2
141	Izubuchi, Taku	izubuchi@bnl.gov	top
	Taku Izubuchi and Chris Dawson for Riken-BNL-Columbia Collaboration
	Improving Full QCD Calculation using Domain-Wall Fermion
	One of the most interesting topics in lattice QCD is unquenched investigations using lattice fermions with good chiral properties. A natural candidate is the domain-wall fermions method, which has numerous attractive features confirmed in quenched calculations. However some pioneering efforts for dynamical QCD using domain-wall fermions have revealed that the breaking of chiral symmetry is largae, likely caused by 5D translationally invariant modes. We try to reduce this chiral symmetry violation by adding the dynamical effect of 4D Wilson fermions with $O(1/a)$ negative mass, which we expect to eliminate the 5D translational invariant modes but to leave the low energy spectrum uneffected. We also discuss other ideas for better chiral symmetry.
	parallel talk	Chiral fermions and gauge theories   3
142	Janke, Wolfhard	janke@itp.uni-leipzig.de	top
	Wolfhard Janke (1) and Ralph Kenna (2) (1) Universit"at Leipzig, Germany (2) Trinity College Dublin, Ireland
	Phase transition strengths from the density of partition function zeroes
	We present a numerical technique employing the density of partition function zeroes which allows to distinguish between phase transitions of first and higher order. We examine the crossover between such phase transitions and demonstrate how to measure the strength of first- and second-order phase transitions in the form of latent heat and critical exponents. These techniques are illustrated in applications to a number of models for which zeroes are available. W. Janke and R. Kenna, J. Stat. Phys. 102 (2001) 1211.
	parallel talk	Spin models   2
143	Jansen, Karl	Karl.Jansen@desy.de	top
	Karl Jansen
	Cost of dynamical quark simulations
	[Panel statement]
	plenary talk
144	Jansen, Karl	Karl.Jansen@desy.de	top
	Pilar Hernandez, Karl Jansen, Laurent Lellouch, Hartmut Wittig
	Scalar Condensate and light-quark masses from overlap fermions
	We explore various ways of determining the non-perturbatively renormalized scalar condensate and light quark masses. The source of this information are pion propagators computed with overlap fermions in the quenched approximation. We compare our results with those obtained from simulations using Wilson fermions.
	poster	Chiral fermions and gauge theories
145	Joerg, Thomas	jorg@itp.unibe.ch	top
	Peter Hasenfratz, Simon Hauswirth, Kieran Holland, Thomas Joerg, Ferenc Niedermayer
	Quark condensate and conserved chiral currents with a chirally symmetric action
	We measure the quark condensate in quenched QCD using the parametrized fixed-point Dirac operator as input for the overlap construction. We also present a general and practical construction of conserved axial and axial-vector currents.
	parallel talk	Chiral fermions and gauge theories   3
146	Johnston, Des	des@ma.hw.ac.uk	top
	W Janke D Johnston M Stathakopoulos
	Fat Fisher Zeroes
	We discuss the analytical caclulation of partition function zeroes for the Ising model on "fat" (planar) random graphs and compare the results with regular 2D lattices.
	parallel talk	Quantum gravity and random surfaces   2
147	Joo, Balint	bj@phys.columbia.edu	top
	B. Joo (UKQCD Collaboration)
	Instabilities in Molecular Dynamics integrators used in HMC
	We discuss an instability in the leap frog integration algorithm, widely used in current Hybrid Monte Carlo (HMC) lattice QCD simulations. This instability is well understood in the case of HMC for the simple oscillator (SHO). We show that for the SHO, the instability problem persists and becomes worse for higher order integration schemes. We demonstrate that the instability is also present in HMC simulations of lattice QCD, and and discuss the implications for future dynamical fermion simulations with light quarks.
	parallel talk	Algorithms and machines   3
148	Juge, Jimmy	juge@fnal.gov	top
	Charm Quark Mass Renormalization at Two Loop Order
	The truncation of the perturbative series at one loop order for the mass renormalization constants remain a significant systematic uncertainty in the determination of heavy quark masses in lattice QCD. We present here a high beta Monte Carlo calculation of the two loop mass renormalization constant for clover-improved fermions near the charm mass in the Fermilab heavy quark formalism.
	poster	Improvement and renormalization
149	Kaczmarek, Olaf	okacz@physik.uni-bielefeld.de	top
	O. Kaczmarek, F. Karsch, P. Petreczky and F. Zantow
	Short distance physics with heavy quark potentials
	We present lattice studies of heavy quark potentials in the quenched approximation of QCD at finite temperatures. Both, the color singlet and color average potentials are calculated. While the potentials are well known at large distances, we give a detailed analysis of their short distance behaviour (from 0.015 fm to 1 fm) near the critical temperature. At these distances we expect that the T-dependent potentials go over into the zero temperature potential. Indeed, we find evidence that the temperature influence gets suppressed for short distances and the running coupling starts to become a unique function of the underlying distance scale. We use this to normalize the heavy quark potentials at short distances and extract the free energy of the quark system in a gluonic heat bath. Our results for the singlet and averaged potentials are in agreement with simple color averaging considerations. We suggest that this approach can be used to construct an order parameter for the confinement phase transition, which survives the continuum limit.
	poster	Non-zero temperature and density
150	Kajantie, Keijo	keijo.kajantie@helsinki.fi	top
	K. Kajantie et al.
	Critical Behaviour in the Ginzburg-Landau Theory in Type-II Region
	poster	Higgs Yukawa SUSY theories
151	Kaneko, Takashi	takashi.kaneko@kek.jp	top
	Takashi Kaneko
	Light hadron spectrum and quark masses
	[plenary talk]
	plenary talk
152	Kenna, Ralph	rak@maths.tcd.ie	top
	W. Janke and R. Kenna
	Exact Finite-Size Scaling with Corrections in the Two Dimensional Ising Model with Special Boundary Conditions
	The Ising model with Brascamp-Kunz boundary conditions has a partition function more amenable to analysis than its counterpart on a torus. This fact is exploited to {\em{exactly}} determine the full finite-size scaling behaviour of the Fisher zeroes of the model. Exact results are also determined for the scaling of the specific heat at criticality, for the specific heat peak and for the pseudocritical points. All corrections to scaling are found to be analytic and the shift exponent $\lambda$ does not coincide with the inverse of the correlation length exponent $1/\nu$.
	poster	Spin models
153	Kikukawa, Yoshio	kikukawa@eken.phys.nagoya-u.ac.jp	top
	Yoshio Kikukawa
	Analytic progress on exact lattice chiral symmetry
	[plenary talk]
	plenary talk
154	Kim, Seyong	skim@kunja.sejong.ac.kr	top
	Seyong Kim and Shigemi Ohta
	Zero temperature phase structure of multi-flavor QCD
	In order to investigate phase structures of many flavored QCD, simulations are being performed with the number of staggered quark flavors, $N_f$ = 6, 8, 10 and possibly higher on a series of lattice volumes for various quark masses. Here, we report our preliminary result of.
	parallel talk	Topics in gauge theories   1
155	Knechtli, Francesco	knechtli@pizero.colorado.edu	top
	Simulating Dynamical Fermions with Smeared Links
	Smearing the gauge links improves the chiral properties of lattice fermions. Recently we proposed the hypercubic smearing (HYP) that improves the flavor symmetry of staggered fermions by an order of magnitude with only minimal distortions at small distances. We describe a new algorithm to simulate dynamical HYP fermions based on the standard pure gauge overrelaxation and heatbath updates. The algorithm has been used to simulate two and four flavors of staggered fermions. Unlike standard dynamical simulation techniques, this algorithm does not loose efficiency at small quark masses.
	parallel talk	Algorithms and machines   2
156	Koma, Yoshiaki	koma@hep.s.kanazawa-u.ac.jp	top
	Yoshiaki Koma, DESY-ITEP-KANAZAWA collaboration
	Monopole dynamics in full QCD
	The properties of monopole extracted by maximally Abelian projection within the full QCD are presented. The lattice size is 24^3X48 for beta=5.29, kappa=0.1355, and 16^3X32 for beta=5.29, kappa=0.1350. Contents are the following: (1) various static potentials (non-Abelian, Abelian, monopole), (2) characteristic properties of monopoles, (3) effective monopole action. Comparison of these results with that of quenched approximation corresponding to beta=6.0 is also discussed.
	parallel talk	Topology and confinement   8
157	Korthals Altes, Chris	altes@cpt.univ-mrs.fr	top
	P. Giovannangeli C. P. Korthals Altes
	Wilson loops and 't Hooft loops in Hot QCD
	Spatial 't Hooft (Wilson) loops measure the electric (magnetic) flux in the plasma. Both have an area law. We explain how the semiclassically computed behaviour of the 't Hooft loop is well explained by the familiar picture of the plasma as consisting of free electrically charged quasi particles, the gluons. The Wilson loop can be computed by assuming a component of magnetically charged quasi-particles. The ratios of multiply charged Wilsonloops obtained on the lattice are consistent with this model
	parallel talk	Topology and confinement   6
158	Kovacs, Tamas	kovacs@ifh.de	top
	T. Kovacs
	Fermion actions and the unquenched topological susceptibility
	We compare the performance of different Wilson-type fermion actions concerning both the detection and the suppression of topological charge fluctuations. Real modes in the physical part of the spectrum of the Dirac operator are used to measure the charge. The fermionic determinant is approximated by a truncation to low eigenmodes in each topological sector. We also comment on how the chiral properties of the fermion action might affect unquenched measurements of the topological susceptibility.
	parallel talk	Topology and confinement   6
159	Kratochvila, Slavo	kslavo@student.ethz.ch	top
	Slavo Kratochvila
	Testing dimensional reduction in SU(2) Gauge Theory
	The effective couplings of dimensionally reduced SU(2) gauge theory are determined numerically, and compared with their theoretically determined values, as a function of temperature.
	parallel talk	Non-zero temperature and density   4
160	Kuramashi, Yoshinobu	yoshinobu.kuramashi@kek.jp	top
	S.Aoki, Y.Kuramashi and S.Tominaga
	Relativistic Heavy Quarks on the Lattice
	Lattice QCD should allow quantitative predictions for the heavy quark physics from first principles. Up to now, however, most approaches have based on the nonrelativistic effective theory, with which the continuum limit can not be taken in principle. In this paper we investigate feasibility of relativistic approaches to the heavy quark physics in lattice QCD. We first examine validity of the idea that the use of the anisotropic lattice could be advantageous to control the $m_Q a$ corrections. Our perturbative calculation, however, reveals that this is not true. We instead propose a new relativistic approach to handle heavy quarks on the isotropic lattice. We explain how power corrections of $m_Q a$ can be avoided and remaining uncertainties are reduced to be of order $(a\Lambda_{\rm QCD})^2$.
	parallel talk	Heavy quark physics   1
161	Kurth, Martin	mkurth@hep.phys.soton.ac.uk	top
	Martin Kurth and Rainer Sommer
	An explicit example of Heavy Quark Effective Theory at one-loop order of perturbation theory
	We consruct correlation functions of the axial current of a light and a heavy quark, both in the static approximation and in full QCD, using the lattice regularization. We discuss the difference between both theories in the continuum limit as well as the mass-dependence of discretization errors.
	parallel talk	Heavy quark physics   1
162	Kurth, Stefan	skurth@physik.hu-berlin.de	top
	Stefan Kurth, Ulli Wolff
	The Renormalized Quark Mass in the Schr"odinger Functional at 1-loop Order
	The renormalized quark mass in the Schr"odinger functional is studied at 1-loop order of perturbation theory with non-vanishing background field. The critical mass, at which the renormalized mass vanishes, is determined at 1-loop order and is used to compute the discretization errors of the Schr"odinger functional coupling at 2-loop order of perturbation theory. The renormalization constant of the pseudo scalar density is calculated at 1-loop order.
	poster	Improvement and renormalization
163	Kuti, Julius	jkuti@ucsd.edu	top
	Julius Kuti
	The QCD String Spectrum and Two-Dimensional Conformal Field Theory
	The low energy excitation spectrum of the critical Wilson surface is discussed between the roughening transition and the continuum limit. The problem is analyzed within the framework of two-dimensional conformal field theory. Difficulties with a simple string theory interpretation of the confining flux are presented.
	parallel talk	Topology and confinement   5
164	Lacagnina, Giuseppe	gnl@ph.ed.ac.uk	top
	G. Lacagnina (UKQCD collaboration)
	Semi-leptonic decays of heavy mesons in quenched lattice QCD
	We present the results of a lattice calculation of matrix elements relevant to semi-leptonic decays of heavy mesons. The form factors relevant to the semi leptonic B->D* decay are calculated and used to extract the Isgur-Wise function and the Vcb element of the CKM matrix.
	parallel talk	Heavy quark physics   3
165	Lang, Christian B.	christian.lang@uni-graz.at	top
	C. Gattringer, M. Goeckeler, C. B. Lang, P. Rakow, A. Schaefer
	Spectral flow for chirally improved Dirac operators
	We discuss a systematic study of several lattice Dirac operators with improved chiral behaviour. For 4d SU(3) gauge configurations on lattices of size up to 16^4 and 6x20^3 we determine spectral properties, in particular the low lying eigenmodes, and their behaviour with regard to projection to an overlap operator. As starting operator we use the original Wilson operator as well as a recently systematically constructed chirally improved operator. We study the flow of eigenvalues and compare the numerical stability and efficiency of the improved operator with that of others. We find intriguing relationships between geometrically localized objects (instantons) and the eigenvalue spectrum.
	parallel talk	Topology and confinement   3
166	Langfeld, Kurt	kurt.langfeld@uni-tuebingen.de	top
	K. Langfeld, E.-M. Ilgenfritz, H. Reinhardt
	Gauge potential singularities and the high temperature phase of SU(2) YM theory
	The continuum limit of SU(2) lattice gauge theory is carefully investigated at zero and at finite temperatures. It is shown that the continuum gauge field acquires singularities originating from the underlying gauged Z_2 Ising model recovered in Landau gauge. Our numerical results show that the density of these singularities properly extrapolates to the continuum limit and is non-vanishing. The action density of this Z_2 Ising links is identified with the gluon condensate. We find for temperatures larger than the deconfinement temperature that the energy density carried by the Z_2 fields obey a Stefan-Boltzmann law. Hence, significant corrections to the Stefan Boltzmann constant corresponding to three gluonic degrees of freedom is expected in the case of SU(2) lattice gauge theory properly extrapolated to the continuum limit.
	parallel talk	Non-zero temperature and density   1
167	Lee, Dean	dlee@physics.umass.edu	top
	Dean Lee Nathan Salwen
	Dynamical Fermions in Hamiltonian Lattice Gauge Theory
	We investigate quenched, partially quenched, and unquenched lattice gauge theories within a Hamiltonian framework. Our approach is based on a diagonalization/Monte Carlo strategy, where the most "important" fermionic interactions are treated exactly.
	parallel talk	Algorithms and machines   1
168	Lee, Frank	fxlee@gwu.edu	top
	F.X. Lee, Leming Zhou (George Washington U. and Lattice Hadron Physics Collaboration), D.B. Leinweber, J. Zanotti (Adelaide University), S. Choe (Hiroshima University)
	N* Masses from an Anistropic Lattice QCD Action
	We report N* masses in the spin 1/2 and 3/2 sectors from a highly-improved anisotropic action. States with both positive and negative parity are isolated via parity projection methods. The extent to which spin projection is required to isolate the spin 3/2 sector is examined. In most cases, good signals are observed with smeared fermion sources and 500 configurations. The gross features of the splittings from the nucleon ground state show a trend consistent with experimental results at the quark masses explored. The challenge of resolving the details of the splittings across different particle channels is addressed.
	parallel talk	QCD spectrum and quark masses   4
169	Lee, Weonjong	wlee@gita.lanl.gov	top
	T. Bhattacharya, G. Fleming, R. Gupta, G. Kilcup, W. Lee, S. Sharpe
	Weak matrix elements for CP violation
	We present preliminary results of the weak matrix elements and bag parameters for four-fermion operators relevant to CP violation. This calculation is being done using staggered fermions.
	poster	Hadronic matrix elements
170	Lepage, Peter	gpl@mail.lns.cornell.edu	top
	Peter Lepage
	Constrained curve fitting for lattice QCD
	[plenary talk]
	plenary talk
171	Levkova, Ludmila	ludmila@phys.columbia.edu	top
	Ludmila Levkova
	Anisotropic Lattices and Dynamical Fermions
	We report results from full QCD calculations with two flavors of dynamical staggered fermions on anisotropic lattices. The physical anisotropy as determined from spatial and temporal masses, their corresponding dispersion relations, and spatial and temporal Wilson loops is studied as a function of the bare gauge anisotropy and the bare velocity of light appearing in the Dirac operator. The anisotropy dependence of staggered fermion flavor symmetry breaking is also examined. These results will then be applied to the study of 2-flavor QCD thermodynamics.
	parallel talk	QCD spectrum and quark masses   1
172	Lewis, Randy	randy.lewis@uregina.ca	top
	Randy Lewis, Nilmani Mathur and R. M. Woloshyn
	Spin splittings among charmed hadrons
	The masses of singly and doubly charmed baryons having spin-1/2 and spin-3/2 are obtained in the quenched approximation from a tadpole-improved anisotropic gauge field action and a D234 quark action. These baryon spin splittings are compared to charmed meson spin splittings obtained from the same lattice action. The results of this comparison are discussed in the context of quark model predictions, heavy quark symmetry predictions and experimental data.
	parallel talk	Heavy quark physics   2
173	Lin, C.-J. David	dlin@hep.phys.soton.ac.uk	top
	SPQR Collaboration
	$K\rightarrow\pi\pi$ matrix elements beyond the leading-order chiral expansion
	We present a lattice study of non-leptonic kaon decay matrix elements with Wilson-type fermions. We focus on those matrix elements relevant for the $\Delta I = 1/2$ rule and $\epsilon^{\prime}/\epsilon$. In particular, we present results of $\Delta I = 3/2$ matrix elements for both CP conserving and CP violating processes. These matrix elements are obtained with two pions in the final state in the numerical simulation. The next-to-leading order contributions in the chiral expansion of these operators are studied and included. Many features of the strategy in calculating these $\Delta I = 3/2$ matrix elements can be applied to our on-going study of $\Delta I = 1/2$, $K\rightarrow\pi\pi$ decays.
	parallel talk	Hadronic matrix elements   3
174	Lippert, Thomas	lippert@theorie.physik.uni-wuppertal.de	top
	Thomas Lippert
	Cost of dynamical quark simulations
	[Panel statement]
	plenary talk
175	Lippert, Thomas	lippert@theorie.physik.uni-wuppertal.de	top
	Thomas Lippert
	A comparative study of numerical methods for the overlap operator and its inverse
	Quite a variety of numerical methods is available to deal with the QCD overlap operator and to solve the associated linear system. The favorite algorithms are polynomial approximations, Lanczos procedures, partial fraction and continued fraction methods. This conribution gives a status report of an interdisciplinary study, carried out together with numerical analysts, that aims at a comparison of standard overlap solvers and novel variants in a realistic quenched QCD setting.
	poster	Algorithms and machines
176	Liu, Guofeng	gfliu@phys.columbia.edu	top
	Guofeng Liu
	Low-lying Dirac Eigenmodes from Domain Wall Fermions
	The Kalkreuter-Simma method is used to determine the low-lying eigenvectors and eigenvalues of the five-dimensional domain wall fermion Dirac operator. We describe this procedure and the resulting eigenvalues and eigenvectors for pure gauge configurations generated with both the Wilson and Iwasaki actions. These results are used to predict the spectral density, $\rho(\lambda)$, for the corresponding four-dimensional Dirac operator and to discuss the character of the near-zero modes arising from gauge field winding number.
	parallel talk	Topology and confinement   3
177	Liu, Keh-Fei	liu@pa.uky.edu	top
	Balint Joo, University of Edinburgh Ivan Horvath, University of Kentucky Keh-Fei Liu, University of Kentucky
	Noisy Monte Carlo Algorithm for Dynamical Fermions
	We report on the recent progress made with the Noisy Monte Carlo (NMC) algorithm for dynamical fermions. We use a quenched heatbath algorithm for gauge updating with a shifted gauge coupling to minimize fluctuations in Tr Ln M. We present data which gives us confidence that the algorithm behaves correctly by comparing 2-flavour Wilson-fermion NMC results with those obtained from Hybrid Monte Carlo, and also demonstrate that we have good control over the amount of noise. We also discuss its potential application to non-degenerate flavors and a finite density algorithm in the canonical ensemble.
	parallel talk	Algorithms and machines   3
178	Liu, Yubin	liu@hiroh2.hepl.hiroshima-u.ac.jp	top
	QCD-TARO Collaboration S.Choe, Ph.de Forcrand, M.Garcia Perez, S.Hioki, Y.Liu, H.Matsufuru, O.Miyamura, A.Nakamura, I.-O.Stamatescu, T.Takaishi, T.Umeda
	Screening mass responses with respect to chemical potential at finite temperature
	A formulation to obtain the response of hadron masses to the chemical potential is developed on the lattice. As the first trial, screening masses of pseudoscalar and vector mesons and their responses are evaluated. We present results on a $16\times 8^2\times 4$ lattice with $n_f=2$ staggered fermions below and above $T_c$. The responses to both the isoscalar and isovector chemical potentials are sizable and they show different behaviors in low and high temperature phases, which may be a consequence of the chiral restoration.
	parallel talk	Non-zero temperature and density   5
179	Loll, Renate	loll@aei-potsdam.mpg.de	top
	J. Ambjorn, A. Dasgupta, J. Jurkiewicz, R. Loll
	A Lorentzian cure for Euclidean troubles
	After giving a brief review of the aims of discrete Lorentzian quantum gravity, I will outline some recent advances of this approach. In doing so I will concentrate on the evidence from both numerical simulations and a continuum analysis that the conformal divergence which has plagued Euclidean gravitational path integrals is absent from suitably defined non-perturbative path integrals over {\it Lorentzian} geometries.
	parallel talk	Quantum gravity and random surfaces   2
180	Lucini, Biagio	lucini@thphys.ox.ac.uk	top
	B. Lucini and M. Teper
	Confining strings in SU(N) gauge theory
	We present results of a numerical study of SU(N) gauge theory in the limit of large N. In particular, we discuss high-klity strings, which are stable for N>4. The ratio $\sigma_k/\sigma_f$ ($\sigma_f$ being the string tension of the fundamental representation) gives new insights on colour confinement.
	parallel talk	Topology and confinement   5
181	Luscher, Martin	luscher@mail.cern.ch	top
	Martin Luscher
	Lattice QCD on PCs?
	[plenary talk]
	plenary talk
182	Mackenzie, Paul	mackenzie@fnal.gov	top
	Paul Mackenzie, Peter Lepage, and Howard Trottier
	Highly improved staggered fermions.
	We present a new action for highly improved staggered fermions. We show that perturbative calculations for the new action are well-behaved where those of the conventional staggered action are badly behaved. We discuss the effects of the new terms in controlling flavor mixing, and discuss the design of operators for the action.
	poster	Improvement and renormalization
183	Mandula, Jeffrey	jeffrey.mandula@science.doe.gov	top
	Jeffrey E. Mandula
	Observations on the Relationship between the Laplacian and Landau Gauges
	The Laplacian Gauge is, by construction, always free of Gribov copies, and it satisfies the Landau Gauge condition in the absence of interactions. We show that this property remains true to first order in Lattice Perturbation Theory, and examine it numerically beyond perturbation theory.
	parallel talk	Theoretical developments   1
184	Manke, Thomas	manke@phys.columbia.edu	top
	X. Liao and T. Manke
	Relativistic Bottomonium Spectrum from Anisotropic Lattices
	We report on our results from a fully relativistic simulation of the quenched bottomonium spectrum. Using an anisotropic formulation of Lattice QCD, we were able to retain a very fine resolution into the temporal direction for a range of different lattice spacings. At fixed renormalised anisotropy we study the scaling properties of the spectrum and compare our results with non-relativistic calculations.
	parallel talk	Heavy quark physics   2
185	Marchetti, Pieralberto	marchetti@pd.infn.it	top
	Pieralberto Marchetti
	Monopole fields from vortex sheets reconciling Abelian and center dominance
	[plenary talk]
	plenary talk
186	Markum, Harald	markum@tuwien.ac.at	top
	E. Bittner, M.-P. Lombardo, H. Markum, R. Pullirsch
	Lowest Eigenvalues of the Dirac Operator for Two Color QCD at Chemical Potential
	An investigation of the spectrum of the staggered Dirac matrix in U(1) and SU(3) gauge theories exhibited universality concerning the low-lying eigenvalues. One observes that in the phase in which chiral symmetry is spontaneously broken the distribution $P(\lambda_{\min})$ and the microscopic spectral density $\rho_s(z)$ are described by chiral RMT. When chiral symmetry is restored one has to rely on ordinary RMT with the related space-time symmetries, but one finds for our lattice size only universal behavior of the macroscopic density $\rho(\lambda)$. Scheduled for this conference, we are analyzing the lowest eigenvalues in the case of two-color QCD both across the temperature phase transition and with the onset of a chemical potential.
	poster	Non-zero temperature and density
187	Martinelli, Guido	guid.martinelli@roma1.infn.it	top
	Guido Martinelli
	Matrix elements
	[plenary talk]
	plenary talk
188	Mathur, Nilmani	mathur@pa.uky.edu	top
	Nilmani Mathur, Randy Lewis, and R.M. Woloshyn
	Heavy Baryons from Lattice NRQCD
	The mass spectrum of heavy quark baryons has been computed on an anisotropic lattice using quenched lattice nonrelativistic QCD. The mass splittings between spin-1/2 and spin-3/2 baryons are also calculated. Results are compared to those obtained by using a Dirac-Wilson action of the D234 type. Color hyperfine effects in heavy baryons is also discussed.
	parallel talk	Heavy quark physics   5
189	Matsufuru, Hideo	matufuru@yukawa.kyoto-u.ac.jp	top
	H. Matsufuru, T. Onogi, T. Umeda
	Anisotropic O(a) improved Wilson quark action and hadron spectroscopy
	We study the O(a) improved Wilson quark action on the quenched anisotropic lattice with the renormalized anisotropy $\xi = 4$. The anisotropy parameter of quark is determined using the dispersion relation of mesons at three values of lattice spacing (1-2 GeV for spatial lattice cutoff) in the quark mass region less than and around the charm quark mass. As applications, we calculate the spectra of light hadrons and heavy-light (charmed) hadrons, and discuss the effect of systematic uncertainty induced in the tuning of anisotropy parameter.
	parallel talk	Improvement and renormalization   3
190	Mawhinney, Robert	rdm@physics.columbia.edu	top
	R. Mawhinney (RBC Collaboration)
	Lattice Values for the Low Energy Constants of $K \rightarrow \pi\pi$ Matrix Elements
	Using quenched domain wall fermions and chiral perturbation theory, we have determined lattice $K \rightarrrow \pi \pi$ matrix elements from $K \rightarrow \pi$ and $K \rightarrow |0\rangle$ matrix elements for $a^{-1} \sim 2$ GeV. Since such a determination involves the subtraction of power divergent quantities, we must understand higher order effects in quenched chiral perturbation theory, the effects of finite $L_s$ for domain wall fermions and the role of topological near-zero modes. We discuss how these effects enter and are handled for representative exchange, gluonic penguin and electroweak penguin operators. This leads to our lattice values for the relevant low-energy constants $\alpha^{(27,1)}_{\rm lat}$, $\alpha^{(8,1)}_{1, \rm lat}$ and $\alpha^{(8,8)}_{\rm lat}$, which are needed to determine physical $K \rightarrow \pi \pi$ matrix elements.
	parallel talk	Hadronic matrix elements   2
191	Maynard, Christopher	cmaynard@ph.ed.ac.uk	top
	UKQCD collaboration C.M. Maynard
	Heavy-light mesons on the lattice
	Matrix elements of decays of heavy-light mesons from lattice QCD, including a preliminary examination of fB on UKQCD's NF=2 configurations.
	parallel talk	Heavy quark physics   4
192	McIntosh, John	jam@physics.unimelb.edu.au	top
	J.A.L. McIntosh and L.C.L. Hollenberg
	Analytic calculation of the mass gap in U$(1)_{2+1}$ lattice gauge theory
	The plaquette expansion method is applied to an analytic calculation of the anti-symmetric mass gap $M$ of compact U$(1)_{2+1}$ in the Hamiltonian formalism. Based on the first four moments of the Hamiltonian with respect to a one-plaquette mean field state the results demonstrate clear scaling of $M$ at and beyond the transition from strong to weak coupling. The scaling parameters determined agree well with the range of numerical determinations available.
	poster	QCD spectrum and quark masses
193	McIntosh, John	jam@physics.unimelb.edu.au	top
	Jesse Carlsson, Lloyd C L Hollenberg, John A L McIntosh, Bruce H J McKellar
	Improved Hamiltonian Lattice Gauge Theory
	This paper is divided into two parts. In the first part, we demonstrate that a direct approach to improving Hamiltonian lattice gauge theory is possible. Our approach is to correct errors in the Kogut-Susskind Hamiltonian by incorporating additional gauge invariant terms. The coefficients of these terms are chosen so that the order $a^2$ classical errors vanish. In the second part we demonstrate the use of the improved Hamiltonian in variational and coupled cluster calculations of the vacuum energy density, specific heat and mass gap for SU(2) and SU(3) gauge theories.
	poster	Improvement and renormalization
194	McNeile, Craig	mcneile@amtp.liv.ac.uk	top
	Craig McNeile
	Hadron spectroscopy of twisted mass lattice QCD at beta = 6.0
	I report on studies of the hadron spectroscopy of O(a) improved twisted mass lattice QCD with simulation parameters of 16**3x48, beta = 6.0. I will also present results for the eigenvalue spectrum and pseudospectra of the twisted mass QCD action.
	parallel talk	QCD spectrum and quark masses   4
195	Meurice, Yannick	yannick-meurice@uiowa.edu	top
	Y. Meurice
	How to make perturbative series converge by cutting off large field configurations
	We show numerically in two lambda phi 4 problems that cutting off the large field configurations cures the divergence of perturbation theory. At sufficiently large coupling, this procedure outperforms Pade's approximants. We explain the universal features of the errors associated with this procedure in terms of lattice inequalities. We discuss the continuum limits of these inequalities. We discuss the extension of this procedure for lattice gauge theory.
	parallel talk	Spin models   2
196	Michael, Chris	c.michael@liv.ac.uk	top
	C. McNeile and C. Michael
	The strangeness content of the nucleon.
	We evaluate the matrix element of $\bar{q} q$ in hadron states on a lattice. We find substantial mixing of the connected and disconnected contributions so that the lattice result that the disconnected contribution to the nucleon is large does not imply that the $\bar{s} s$ content is large.
	parallel talk	Hadronic matrix elements   1
197	Miller, Travis	tmiller@artsci.wustl.edu	top
	Travis R. Miller and Michael C. Ogilvie
	Nonequilibrium phenomena in Finite Temperature SU(3) Gauge Theory
	After a rapid increase in system temperature across the deconfinement temperature T_d, the subsequent evolution of the Polyakov loop towards equilibrium is governed by the equilibrium effective action. Metastability is observed for a range of temperatures from T_d to T_s, with spinodal decomposition dominating equilibration above T_s. From nonequilibrium simulations, we reconstruct the equilibrium effective action, and estimate key observables associated with spinodal decomposition, nucleation, and relaxation. Using several methods, we measure k_c, the critical wavelength associated with spinodal decomposition. Late-stage relaxation towards equilibrium is controlled by the Debye screening mass m_D.
	parallel talk	Non-zero temperature and density   7
198	Mitrjushkin, Valentin	vmitr@thsun1.jinr.ru	top
	V.K. Mitrjushkin, A.I. Veselov
	An interpolating gauge between no-gauge and Maximally Abelian gauge in SU(2) lattice theory.
	Gauge variant gluon propagators are calculated in SU(2) lattice gauge theory for the different choices of the gauge fields. Different choices of Lorentz (or Landau) gauge fixing condition are compared.
	parallel talk	Topics in gauge theories   1
199	MJAHED, Mostafa	mmjahed@hotmail.com	top
	Classification of Multi-jet Topologies in e+ e - collisions using Multivariate Analysis Methods and Morphological Variables
	A number of interesting studies of e+ e- collisions at LEP2, may be performed using the differences between the topologies of the produced events. In fact, several processes and channels are expected, where hadronic events with multi-jet topologies will be produced, with dominant rates, through the Z or W’s decays. It is obvious that the identification of these abundant processes and the tagging of these multi-jet topologies will need analysis techniques which efficiently discriminate between very noisy data and very overlapped classes of events. We propose, in this paper, to use a new kind of variables usually used in image processing and recognition problems as the elongation, the compactness, the invariant moments and the polar signature. These so-called morphological variables, are comparable to the classical sphericity, aplanarity. The amelioration of the recognition efficiency is gotten thanks to the use of several multivariate analysis methods. As linear classifiers, the linear discriminant analysis, the binary decision tree and a minimal distance technique are achieved. As non-linear classifiers, we used non-linear discriminant analysis as well as a back-propagation neural network. Applied to four classes of ALEPH simulated events (corresponding to 2 jets, 3 jets, 4 jets and n jets events, n>4), these multivariate classifiers allowed us to notice a good classification compared to the classical univariate cuts. Neural network have proven themselves to be more efficient classifier than the other techniques. The efficiencies and purities achieved with the optimized neural network are in average 1 to 7 % higher than those obtained with the four others methods.
	poster	Algorithms and machines
200	Molodtsov, Serguei	molodtsov@vitep5.itep.ru	top
	S.V.Molodtsov and G.M.Zinovjev
	Instanton liquid at finite baryon density
	We study the interactions of light quarks in the instanton liquid at nonzero density of quark matter. The behaviour of dynamical quark mass, chiral and diquark condensates together with the instanton liquid density are investigated as the functions of quark chemical potential. The possibility of realizing the colour superconducting phase of dense QCD is estimated.
	poster	Non-zero temperature and density
201	Molodtsov, Serguei	molodtsov@vitep5.itep.ru	top
	S.V.Molodtsov, A.M.Snigirev, G.M.Zinovjev
	Quark interactions in the instanton liquid
	The selfconsistent approach to the quark interactions in the instanton liquid is developed within the tadpole approximation calculating the basic functional integral. The effective Lagrangian obtained includes colourless scalar field interacting with quarks. The origin of this dynamical field as an interaction carrier in soft momentum region is discussed.
	poster	QCD spectrum and quark masses
202	Moore, Guy	guymoore@phys.washington.edu	top
	Guy D. Moore
	Atomic Bose-Einstein condensation and the lattice
	The condensation temperature of a bosonic atomic gas is corrected by atomic interactions. Surprisingly, the effective theory determining the shift in the transition temperature shows nonperturbative physics best solved by lattice techniques similar to those applied to study the electroweak phase transition on the lattice.
	parallel talk	Spin models   1
203	Moutarde, Herve	herve.moutarde@cpht.polytechnique.fr	top
	Ph. Boucaud, J.P. Leroy, H. Moutarde, J. Micheli, O. Pene, J. Rodriguez-Quintero, C. Roiesnel
	Preliminary calculation of alpha_s from Green functions with dynamical quarks.
	We present preliminary results on the computation of the QCD running coupling in the \tilde{MOM} scheme and Landau gauge with two flavours of dynamical Wilson quarks. Gluon momenta range up to about 7 GeV (\beta=5.6, 5.8 and 6.0) with a constant dynamical mass. This range allows already to exhibit some evidence for a sizeable 1/p^2 correction to the asymptotic behaviour, as in the quenched approximation.
	poster	QCD spectrum and quark masses
204	MUROYA, Shin	muroya@yukawa.kyoto-u.ac.jp	top
	S.Choe, S.Muroya, A.Nakamura, C.Nonaka, T.Saito and F.Shoji
	Lattice Tool Kit in Fortran90
	We have written a simulation code, LTKf90, for lattice QCD. It includes quench update (pseudo heatbath and Metropolis), solver with Wilson fermions and Hybrid Monte Carlo part. We intend to offer not libraries but elements to construct more efficient and/or complicated programs. It is available from http://pan.ias.hiroshima-u.ac.jp/~LTK/ All routines are written in Fortran90. As demonstrated by Dasgupta, Levi, Lubicz and Rebbi (hep-lat/9612015), Fortran90's new features, especially module, are powerful to realize simple codes close to original mathematical expressions. The code runs on many platforms not at the highest performance, but at reasonable speed. We report its performance on SX5 (shared memory vector), SR8000 (shared memory, pseudo vector), and several distributed memory PC clusters which consist of Compaq alpha and Apple G4 together with Gigabit Ether, Myrinet, and Myrinet2k.
	poster	Algorithms and machines
205	MUSLIH, SAMI	sami_muslih@hotmail.com	top
	Sami I. Muslih
	The Hamilton-Jacobi treatment for an abelian Chern-Simons system
	The abelian Cher-Simons system is treated as a constrained system using the Hamilton-Jacobi approach. The equations of motion are obtained as total differential equations in many variables. It is shown that their simultaneous solutions with the constraints lead to obtain the canonical phase space coordinates and reduced phase space Hamiltonian with out introducing Lagrange multipliers and with out any additional gauge fixing conditions.
	poster	Topics in gauge theories
206	Münster, Gernot	munsteg@uni-muenster.de	top
	Gernot Münster and Christel Kamp
	Distribution of Instanton Sizes in a Simplified Instanton Gas Model
	We investigate the distribution of instanton sizes in the framework of a simplified model for ensembles of instantons. This model takes into account the non-diluteness of instantons. The infrared problem for the integration over instanton sizes is dealt with in a self-consistent manner by approximating instanton interactions by a repulsive hard core potential. This leads to a dynamical suppression of large instantons. The characteristic features of the instanton size distribution are studied by means of analytic and Monte Carlo methods. The numerical Monte Carlo calculations are done in the grand canonical ensemble. In any dimension we find a power law behaviour for small sizes, consistent with the semi-classical results. At large instanton sizes the distribution decays exponentially. The results are compared with those from lattice simulations and indicate that our simplified model reproduces the main features of instanton ensembles with a dynamical infrared cut-off.
	parallel talk	Topology and confinement   4
207	NAKAMURA, Atsushi	nakamura@riise.hiroshima-u.ac.jp	top
	S.Muroya, A.Nakamura, C.Nonaka, M.Sekiguchi and H.Wada
	Study of sigma meson on the lattice
	The sigma meson, iso-singlet scalar particle, plays the central role in QCD chiral symmetry breaking mechanism. Yet it is very obscure whether \sigma is a pole or a simple \pi-\pi correlation effect. Recent reanalysis of the phase shift in \pi-\pi channel by Igi and Hikasa (Phys. Rev. D59, 034005 (1999)) strongly suggests the existence of \sigma whose mass is near to \rho. We have studied I=0 and J^P=0^+ channel by lattice QCD. We construct the channel as (\bar{u}u+\bar{d}d)/\sqrt{2}|0>. Since both connected and disconnected diagrams contribute in the channel, we work in full QCD. Disconnected quark loops are evaluated by a noise method. We use Wilson fermions with Nf=2 at \beta=4.8 (the lattice spacing is about 0.197fm). Although they should be considered preliminary, our numerical data show 1) the disconnected part has large contribution, 2) masses of \sigma and \rho are at the same order although \sigma suffers from larger error bars. We discuss also a) formulation to measure correlations of an operator whose vacuum expectation value does not vanish. b) 0~+ glueball mixing effect.
	poster	QCD spectrum and quark masses
208	Nakayama, Yoichi	yoichi@eken.phys.nagoya-u.ac.jp	top
	Yoshio Kikukawa, Yoichi Nakayama, Hiroshi Suzuki
	On the lattice construction of electroweak gauge theory
	We discuss a lattice construction of electroweak theory with exact gauge invariance, based on the Ginsparg-Wilson relation. Our construction includes the topologically non-trivial sectors of SU(2) gauge fields, while U(1) gauge fields are restricted to the vacuum sector. We show that the global integrability condition is satisfied in the sectors which possess a SU(2) configuration invariant under a certain reflection symmetry.
	poster	Chiral fermions and gauge theories
209	Namekawa, Yusuke	namekawa@het.ph.tsukuba.ac.jp	top
	CP-PACS Collaboration : S.~Aoki, R.~Burkhalter, S.~Ejiri, M.~Fukugita, S.~Hashimoto, N.~Ishizuka, Y.~Iwasaki, K.~Kanaya, T.~Kaneko, Y.~Kuramashi, V.~Lesk, Y.~Namekawa, M.~Okamoto, M.~Okawa, Y.~Taniguchi, A.~Ukawa and T.~Yoshi\'e
	Equation of state for pure SU(3) gauge theory on anisotropic lattices
	We present a study of equation of state for pure SU(3) gauge theory with the plaquette action using anisotropic lattices with the anisotropy $\xi \equiv a_{s}/a_{t} = 2$. The pressure and energy density are calculated on $16^{3} \times 8$, $20^{3} \times 10$ and $24^{3} \times 12$ lattices. Unlike the case of the isotropic lattices, the pressure and energy density are found to satisfy the leading $1/N_{t}^{2}$ behavior from our coarest lattice $N_{t}/\xi=4$. We perform a well controlled continuum extrapolation of the results and find that the pressure and energy density agree with those obtained on isotropic lattices with the same action, but have smaller and more reliable errors.
	parallel talk	Non-zero temperature and density   5
210	Necco, Silvia	necco@ifh.de	top
	Rainer Sommer, Silvia Necco
	The Nf=0 heavy quark potential and perturbation theory
	In the pure gauge theory it is possible to investigate the heavy quark potential at short distances, connecting the short and long ranges in a large volume (64^4 lattice). On the other hand, the lambda parameter is known and this allows a perturbative parameterfree prediction for the force at short distances. We present the simulation results for the force and the potential in the range 0.05-0.8 fm. Perturbation theory is quite accurate up to 0.15 fm and no evidence of non-perturbative effects is seen. The bosonic string description, which is expected to be valid at large distances, is in excellent agreement with our results for surprisingly small distances.
	poster	Improvement and renormalization
211	Neff, Hartmut	neff@theorie.physik.uni-wuppertal.de	top
	H. Neff
	Improving eigenmode calculations for nonhermitian Wilson-type Dirac matrices.
	It will be shown that eigenmode calculations for nonhermitian Wilson-type Dirac matrices can be accelerated substantially by a simple polynomial transformation. In this manner the eigenmode algorithm becomes sensitive to spectral regions close to the real axis, which in general is the physically interesting part of the spectrum.
	parallel talk	Algorithms and machines   1
212	Negele, John	negele@mitlns.mit.edu	top
	R. Brower, S. Chandrasekharan, J. W. Negele, and U.-J. Wiese (LHPC collaboration)
	QCD at Fixed Topology
	Because present Monte Carol algorithms for lattice QCD may become trapped in a given topological charge sector when one approaches the continuum limit, it is important to understand the effect of calculating at fixed topology. In this work, we show that although the restriction to a fixed topological sector becomes irrelevant in the infinite volume limit, it gives rise to characteristic finite size effects due to contributions from all $\theta$-vacua. We calculate these effects and show how to extract physical results from numerical data obtained at fixed topology.
	parallel talk	Topology and confinement   2
213	Nelson, Daniel	nelson@aluminumangel.org	top
	Greg Kilcup George Fleming Daniel Nelson
	Does m_u=0?
	We implemented the Sharpe and Shoresh program for the calculation of the Gasser-Leutwyler coefficients in the QCD chiral lagrangian. Using dynamical n_f=3 simulations we present preliminary results for 2 L_8 - L_5, a combination important in the determination of m_u.
	parallel talk	QCD spectrum and quark masses   1
214	Nicolis, Stam	Stam.Nicolis@phys.univ-tours.fr	top
	P. Dimopoulos,K. Farakos, C. P. Korthals-Altes, G. Koutsoumbas and S. Nicolis
	Branes in the 5D Higgs Model
	We find 3-brane Higgs or Coulommb phases in the 5D Abelian Higgs Model and determine the transition surfaces that separate them from the usual bulk phases.
	parallel talk	Higgs Yukawa SUSY theories   1
215	Noaki, Jun-Ichi	noaki@het.ph.tsukuba.ac.jp	top
	CP-PACS Collaboration: S. Aoki, Y. Aoki, R. Burkhalter, S. Ejiri, M. Fukugita,S. Hashimoto, N. Ishizuka, Y. Iwasaki, T. Izubuchi,K. Kanaya, T. Kaneko, Y. Kuramashi, V. Lesk, K. Nagai, J. Noaki(*), M. Okawa, Y. Taniguchi, A. Ukawa, T. Yoshi\'e
	Calculation of$K\to\pi\pi$ decay amplitudes from $K\to\pi$ matrix elements in quenched domain-wall QCD
	We present a calculation of the hadronic matrix elements for $K\to\pi\pi$ decay within the quenched approximation. Use is made of the relation between the $K\to\pi$ matrix elements, to be computed on the lattice, and those for $K\to\pi\pi$ derived in the framework of chiral perturbation theory at the leading order. In the numerical simulation, the domain-wall fermion formalism and the renormalization group improved gauge action are employed to ensure the required chiral properties. Perturbative renormalization factors at one loop and renormalization group running are applied to obtain the physical $K\to\pi$ matrix elements. The resuls are applied to examine the $\Delta I=1/2$ rule and the value of $\varepsilon'/\varepsiolon$.
	parallel talk	Hadronic matrix elements   3
216	Nobes, Matthew	manobes@sfu.ca	top
	Matthew Nobes Howard Trottier
	Perturbative evaluation of Wilson loops to $O(g^{4})$
	Perturbative calculations are crucial for implementing various improved actions. We have used several techniques that simplify and automate perturbation theory for very complicated lattice actions (quarks and glue). Using these techniques we have calculated the renormalized coupling to one loop order using Symanzik improved glue and with improved staggered fermions. This poster will present our results as well as detail the techniques used to obtain them.
	poster	Improvement and renormalization
217	Nomura, Kouji	nomura@hiroh2.hepl.hiroshima-u.ac.jp	top
	K. Nomura T. Umeda O. Miyamura H. Matufuru
	Study of spatial meson correlations at finite temperature in quenched QCD on anisotropic lattice.
	We analyze the spatial correlation function of meson at finite temperature. To achieve fine resolution in the spatial direction we use an anisotropic lattice with standard Wilson gauge action and O(a) improved Wilson quark action. Below and above Tc, properties of the correlation functions are investigated by two methods: fit with an ansatz for the spectral function (e.g.two poles), and direct reconstruction of the spectral function using the Maximum Entropy Method.
	poster	Non-zero temperature and density
218	NONAKA, Chiho	nonaka@hiroh2.hepl.hiroshima-u.ac.jp	top
	S.Muroya, A.Nakamura and C.Nonaka
	SU(2) Lattice QCD with Finite Chemical Potential
	Using Iwasaki action and Wilson fermion, we study the SU(2) QCD vacuum at finite chemical potential. The ratio of fermion determinants is evaluated at each Metropolis link update process. We calculate expectation values of the Polyakov line, baryon number density and the gluon energy density as a function of chemical potential on $4^4$ and $4^3\times 8$ lattice. Comparing with our previous calculation with the standard plaquete action, we can reach to larger chemical potential, i.e., we have studied the regions 0 \leq \mu*a \leq 0.9 Around $\mu a$ = 0.4 we observe the rapid increase in all physical quantities. These results indicate that we are near to the confinement/deconfinement transition. The expectation value of the pseudo scalar, vector and baryonium (qq) masses are also measured. The results suggest the chiral symmetry restored at high density. In addition to above calculations, we perform the two-color hybrid monte calro simulations at finite density and make a comparison between the two calculations. We study the mechanism of confinement/deconfinement transition and chiral symmetry restored from the hadron at finite chemical potential.
	parallel talk	Non-zero temperature and density   5
219	Ogilvie, Michael	mco@wuphys.wustl.edu	top
	Peter N. Meisinger, Travis R. Miller, and Michael C. Ogilvie
	Phenomenological Equations of State for the Quark-Gluon Plasm
	Two phenomenological models describing an SU(N) quark-gluon plasma are presented. Model A is obtained from a high temperature expansion of the free energy of a massive gluon, while model B is derived by demanding color neutrality over regions of a certain size. Each model has a single free parameter, exhibits behavior similar to lattice simulations over the range T_d-5T_d, and has the correct blackbody behavior for large temperatures. The N=2 deconfinement transition is second order in both models, while N=3,4, and 5 are all weakly first order. Both models appear to have a smooth large-N limit. In both models, the confined phase is characterized by a symmetric arrangement of Polyakov loop eigenvalues that makes the Polyakov loop expectation value zero. In the deconfined phase, the rotation of the eigenvalues in the complex plane towards 1 is responsible for the approach to the blackbody limit over the range T_d-5T_d. Simulations for SU(3) confirm this picture. The addition of massless quarks in SU(3) breaks Z(3) symmetry weakly and eliminates the phase transition.
	parallel talk	Non-zero temperature and density   5
220	Okamoto, Masataka	okamoto@rccp.tsukuba.ac.jp	top
	CP-PACS collaboration: S.~Aoki, R.~Burkhalter, S.~Ejiri, M.~Fukugita, S.~Hashimoto, N.~Ishizuka, Y.~Iwasaki, K.~Kanaya, T.~Kaneko, Y.~Kuramashi, V.~Lesk, K.~Nagai, M.~Okamoto(*), M.~Okawa, Y.~Taniguchi, A.~Ukawa, T.~Yoshi\'e (*) speaker
	Charmonium spectrum from quenched anisotropic lattices
	We present our results of the quenched charmonium spectrum on anisotropic lattices. Simulations are carried out with the standard plaquette gauge action and a mean-field improved asymmetric clover quark action employing $\xi = a_s/a_t = 3$ lattices. We calculate the spectrum of S- and P-states and their excited states. We study the scaling behavior of mass splittings, and compare with the experiment and previous lattice results.
	parallel talk	Heavy quark physics   2
221	Okawa, Masanori	masanori.okawa@kek.jp	top
	JLQCD collaboration: S. Aoki, R. Burkhalter, M. Fukugita, S. Hashimoto, K-I. Ishikawa, N. Ishizuka, Y. Iwasaki, K. Kanaya, T. Kaneko, Y. Kuramashi, M. Okawa, T. Onogi, S. Tominaga, N. Tsutsui, A. Ukawa, N. Yamada, T.~Yoshi\'{e}
	Non-trivial phase structure of N_f=3 QCD with O(a) improved Wilson fermion at zero temperature
	We recently started N_f=3 QCD simulations with O(a) improved Wilson fermion employing exact fermion algorithm which we developed for odd number of flavors. We found that this theory has non-trivial phase structure in the (\beta,\kappa) plane even at zero temperature. We do not observe such phase structure at zero temperature in neither N_f=2 QCD nor N_f=3 QCD with unimproved Wilson fermion. A detailed study is made to understand the nature of the observed phase structure.
	poster	QCD spectrum and quark masses
222	Olejnik, Stefan	fyziolej@savba.sk	top
	M. Faber, J. Greensite, S. Olejnik
	Center Dominance Recovered: Direct Laplacian Center Gauge
	We introduce a variation of direct maximal center gauge fixing: the ``direct Laplacian'' center gauge. The new procedure overcomes certain shortcomings of maximal center gauge, associated with Gribov copies, that were pointed out by Bornyakov et al. in hep-lat/0009035.
	parallel talk	Topology and confinement   2
223	Oliveira, Orlando	orlando@teor.fis.uc.pt	top
	O. Oliveira P. J. Silva
	Gribov copies and gauge fixing in lattice gauge theories
	We address the problem of the Gribov copies in lattice gauge theories. For the Landau gauge, results show that a suitable combination of evolutionary algorithms with traditional steepest descent methods correctly identifies the global maximum of the optimization function. We discuss the performance of the combined algorithm for SU(2) and SU(3) on small cubic lattices.
	poster	Algorithms and machines
224	Onogi, Tetsuya	onogi@yukawa.kyoto-u.ac.jp	top
	Shoji Hashimoto, Tomomi Ishikawa and Tetsuya Onogi
	Nonperturbative calculation of Z_A/Z_V for heavy-light currents using Ward-Takahashi identity
	We determine the ratio of renormalization factors of vector and axial-vector heavy-light currents. The calculation is performed nonperturbatively using the axial Ward-Takahashi identity for the heavy-light currents.
	parallel talk	Heavy quark physics   1
225	Orginos, Konstantinos	kostas@bnl.gov	top
	Konstantinos Orginos for Riken-BNL-Columbia Collaboration
	Chiral properties of Domain Wall Fermions with Improved Gauge actions
	We study the chiral properties of quenched Domain Wall Fermions with several gauge actions. We demonstrate that the nearly translationally invariant modes in the fifth dimension that dominate the residual mass on Wilson Gauge action, can be substantially suppressed using improved gauge actions. In particular the Symanzik action, the Iwasaki action, and other renormalization group inspired gauge actions have been studied and compared to the Wilson action.
	parallel talk	Chiral fermions and gauge theories   1
226	Orth, Boris	orth@theorie.physik.uni-wuppertal.de	top
	Boris Orth (GRAL Collaboration)
	Full QCD beyond the rho decay threshold
	The GRAL project (Going Realistic and Light) aims at simulating N_f=2 QCD below the vector meson decay threshold, m_\pi/m_\rho < 0.5. Working on a number of different spatial lattice volumes we will make use of finite size scaling to measure physical observables. For fixed Wilson action parameters (beta, kappa) several different lattice sizes will be investigated. Finite size effects are exploited in order to extrapolate to the infinite volume prior to the usual chiral and continuum extrapolations. We report on the current status and future prospects of the project.
	poster	QCD spectrum and quark masses
227	ORTIZ, GERARDO	ortiz@viking.lanl.gov	top
	GERARDO ORTIZ
	The challenge of quantum computer simulation of physical phenomena
	[plenary talk]
	plenary talk
228	Pallante, Elisabetta	pallante@he.sissa.it	top
	Maarten Golterman Elisabetta Pallante
	Effects of Quenching and Partial Quenching on Penguin Matrix Elements
	In the calculation of non-leptonic weak decay rates, a ``mismatch" arises when the QCD evolution of the relevant weak hamiltonian down to hadronic scales is performed in unquenched QCD, but the hadronic matrix elements are then computed in (partially) quenched lattice QCD. This mismatch arises because the transformation properties of penguin operators under chiral symmetry change in the transition from unquenched to (partially) quenched QCD. Here we discuss QCD-penguin contributions to $\Delta S=1$ matrix elements, and show that new low-energy constants contribute at leading order in chiral perturbation theory in this case.
	parallel talk	Hadronic matrix elements   3
229	Panagopoulos, Haralambos	haris@ucy.ac.cy	top
	A. Bode, H. Panagopoulos, Y. Proestos
	O(a) improved QCD: The 3-loop beta-function, and the critical hopping parameter.
	We calculate the 3-loop bare $\beta$-function of QCD, formulated on the lattice with the clover fermionic action. The dependence of our result on the number of colors $N$, the number of fermionic flavors $N_f$, as well as the clover parameter $c_{SW}$, is shown explicitly. A direct outcome of our calculation is the two-loop relation between the bare coupling constant $g_0$ and the one renormalized in the $\overline{{\rm MS}}$ scheme. Further, we can immediately derive the three-loop correction to the relation between the lattice $\Lambda$-parameter and $g_0$, which turns out to be very pronounced. We also calculate the critical value of the hopping parameter, $\kappa_c$, in the clover action, to two loops in perturbation theory. This quantity is an additive renormalization; as such, it exhibits a linear divergence in the lattice spacing. We compare our results to non perturbative evaluations of $\kappa_c$ coming from MC simulations.
	poster	Improvement and renormalization
230	Papa, Alessandro	papa@cs.infn.it	top
	Roberto Fiore, Alessandro Papa, Paolo Provero
	Finite size scaling and deconfinement transition in gauge theories
	A new method is proposed for determining the critical indices of the deconfinement transition in gauge theories. The method is based on the finite size scaling behavior of the expectation value of simple lattice operators, such as the plaquette. A precise determination of the critical index $\nu$, in agreement with the prediction of the Svetitsky-Yaffe conjecture, is obtained applying the method to the case of $SU(3)$ pure gauge theory in $(2+1)$ dimensions. Preliminary results for the case of $SU(2)$ pure gauge theory in $3+1$ dimensions are also presented.
	poster	Non-zero temperature and density
231	Papinutto, Mauro	Mauro.Papinutto@roma1.infn.it	top
	D.Becirevic, Ph.Boucaud, V.Gimenez, C.-J.D.Lin, V.Lubicz, G.Martinelli, M.Papinutto, F.Rapuano,C.T.Sachrajda
	K->pi pi matrix elements for epsilon'/epsilon and Delta I = 1/2 rule, with Wilson like fermion.
	We present the status of a lattice calculation for the matrix elements of the Delta S = 1 effective weak Hamiltonian which are relevants in the determination of epsilon'/epsilon and for the Delta I = 1/2 rule, with two pions in the final state and by using Wilson fermions. We discuss some issues about the Goldstone pole contamination of the non-perturbative renormalization constants for Delta I = 3/2 four fermion operators. We study the effects of final state interaction both in the Delta I=1/2 and Delta I=3/2 channels and we show some preliminary results for the matrix elements of the Delta I=1/2 CP-conserving and CP-violating operators. Our quenched simulation are done at beta=6.0, lattice size 24^3*64, with the non-perturbatively improved clover action.
	parallel talk	Hadronic matrix elements   3
232	Patel, Apoorva	adpatel@cts.iisc.ernet.in	top
	A. Patel and R. Ratabole
	Mesons in transverse lattice QCD at strong coupling and large-N
	Mesons in large-N QCD are analysed in light-front coordinates with a transverse lattice at strong coupling. In this limit, their properties can be expressed as simple renormalisations of the 'tHooft model results. Spectrum, light-cone wavefunctions and form factors of various mesons are calculated.
	parallel talk	QCD spectrum and quark masses   4
233	Peardon, Mike	mjp@maths.tcd.ie	top
	Mike Peardon
	Progress in lattice algorithms
	[plenary talk]
	plenary talk
234	Pelissetto, Andrea	Andrea.Pelissetto@roma1.infn.it	top
	S. Caracciolo, A. Montanari, A. Pelissetto
	Nonlinear sigma-models on discrete non-Abelian groups
	We study the two-dimensional renormalization-group flow induced by perturbations that reduce the global symmetry of the $O(3)$ $\sigma$-model to the discrete symmetries of Platonic solids. We estimate the value of the correlation length at which differences in the behaviour of the various models should be expected. For the icosahedron model, we find $\xi\gtapprox 200$. We provide an explanation for the recent numerical results of Patrascioiu and Seiler and of Hasenfratz and Niedermayer.
	parallel talk	Spin models   2
235	Pena, Carlos	Carlos.PenaRuano@roma2.infn.it	top
	M. Guagnelli J. Heitger C. Pena S. Sint A. Vladikas
	$K-\bar{K}$ mixing amplitude with Schr\"odinger Functional and twisted mass QCD
	Schr\"odinger Functional and twisted mass QCD techniques are combined in the computation of renormalized matrix elements of four-fermion operators in lattice QCD. First results for the $K-\bar{K}$ mixing amplitude obtained from this setup will be presented.
	parallel talk	Hadronic matrix elements   2
236	pene, olivier	olivier.pene@th.u-psud.fr	top
	Ph. Boucaud, A. Le Yaouanc, J.P. Leroy, J. Micheli, O. Pene, J. Rodríguez-Quintero
	Consistent OPE Description of Gluon Two- and Three-point Green Function?
	We perform an OPE analysis of the flavorless non-perturbative gluon propagator and the symmetric three-gluon vertex in the Landau gauge. The first subdominant operator is $A_\mu A^\mu$ which can condensate in the Landau gauge ``vacuum'' although being a non-gauge invariant operator. We neglect all higher dimension operators. Then the gluon propagator and the symmetric three gluon vertex only depend on one common unknown condensate. We propose a consistency check from lattice data. At two loops for the leading coefficient and with $1/p^2$ corrections at tree-level order the two fitted values for the condensate do not agree. At three loops we argue that the today unknown $\beta_2^{\rm MOM}$ should be equal to $1.5(3)\times \beta_2^{\widetilde{\rm MOM}}=7400(1500)$ to fulfill the OPE relation. Inclusion of the power corrections' anomalous dimensions should improve further the agreement. We show that these techniques cannot be applied to the asymmetric three gluon vertex with one vanishing momentum.
	parallel talk	Topics in gauge theories   1
237	Pepe, Michele	pepe@th.u-psud.fr	top
	Michele Pepe Philippe de Forcrand Lorenz von Smekal
	A finite size scaling study of interfaces in the 3d Ising model.
	Near the deconfinement temperature, 4d SU(2) Yang-Mills theory is believed to belong to the same universality class as the 3d Ising model. Results of a numerical study on the universal finite size scaling functions for interfaces in the 3d Ising model are reported, with the purpose of learning about the screening properties of SU(2) 't Hooft loops.
	parallel talk	Spin models   2
238	Petersson, Bengt	bengt@physik.uni-bielefeld.de	top
	P. Bialas, Z. Burda, B. Petersson, J. Tabaczek
	Geometry of reduced supersymmetric 4D Yang-Mills integrals and a related surface model
	With the help of numerical simulations we discuss the long distance properties of the models. In particula we show the excistence of one-dimensional configurations in the powerlike tails of the distributions. The generalization to six and ten dimensions are discussed.
	poster	Higgs Yukawa SUSY theories
239	Petrarca, Silvano	petrarca@roma1.infn.it	top
	L.Giusti, M.L.Paciello, S.Petrarca, N. Tantalo, B. Taglienti
	Quark and gluon propagator in the covariant gauge
	Preliminary results on the gluon and quark propagator computed in the covariant gauge for different values of the gauge parameter are presented. Some physical consequences are discussed.
	parallel talk	Theoretical developments   1
240	Petreczky, Peter	petreczk@physik.uni-bielefeld.de	top
	F. Karsch, E. Laermann, P. Petreczky S. Stickan and I. Wetzorke
	Temporal quark and gluon propagators in the deconfined phase
	The temporal quark and gluon propagators in the deconfined phase of QCD are related to the properties of the quasi-particles in the plasma. So far the properties of these quasiparticles were studied only in perturbation theory which is, however, valid only for large temperatures. We have studied the temporal quark and gluon propagators in quenched QCD on 48^3x12 and 64^3x16 lattices at temperatures 1.5 T_c and 3 T_c (T_c is the deconfinement temperature). We calculate the propagator in Coulomb and Landau gauge and perform a detailed comparison with prediction of perturbation theory at 3T_c. Using the Maximal Entropy Method we extract the quark dispersion relation from the lattice propagator in Coulomb gauge.
	parallel talk	Non-zero temperature and density   6
241	Petrov, Konstantin	petrov@physik.uni-bielefeld.de	top
	P.Bialas,A.Morel,B.Petersson,K.Petrov,T.Reisz
	Screening masses in (2+1)D QCD in the plasma phase and the reduced model
	We discuss the low energy spectrum of an SU(3) gauged 2D model for adjoint scalar fields, defined by dimensional reduction of pure gauge QCD in (2+1)D at high temperature. Two colourless bound states, respectively even and odd under the $Z_2$ symmetry related to time reversal in the original theory are identified, which saturate the correlations between Polyakov loops. Their contributions in correlation functions of local composite operators $A_n$ respectively of degree $n=2p$ and $2p+1$ in the scalar fields ($p=1,2$) fulfill factorization. States corresponding to channels with other quantum numbers are discussed.
	poster	Topics in gauge theories
242	Pfeiffer, Hendryk	H.Pfeiffer@damtp.cam.ac.uk	top
	Hendryk Pfeiffer
	The dual of non-Abelian Lattice Gauge Theory and some of its features
	Non-Abelian Lattice Gauge Theory in d>=2 with an arbitrary compact Lie groups as the gauge group is related to a Spin Foam Model by an exact duality transformation [Nucl. Phys. B 598 (2001) p. 400]. The observables of the two models are related in such a way that expectation values in Lattice Gauge Theory correspond to ratios of partition functions in the dual model. Conversely one can find expectation values in the dual model which correspond to the same ratios of partition functions that are currently used in the study of Z_N monopoles in SU(N) gauge theories. This situation parallels the construction of monopole correlators in U(1) Lattice Gauge Theory. I will also comment on the stron-weak nature of this transformation, on how to extract the strong coupling expansion from the dual model and on possible further applications.
	parallel talk	Theoretical developments   1
243	Philipsen, Owe	philipse@mitlns.mit.edu	top
	Non-perturbative parton masses
	A gauge invariant, non-local observable is constructed in lattice pure gauge theory, which is identical to the gluon propagator in a particular gauge. The transfer matrix formalism is used to show that this correlator decays exponentially with eigenvalues of the Hamiltonian. This implies a gauge invariant singularity structure of the propagator in momentum space, permitting a non-perturbative definition of a parton mass. The relation to gauge fixing and the extension to matter fields are discussed.
	parallel talk	QCD spectrum and quark masses   3
244	Pisarski, Rob	pisarski@bnl.gov	top
	A. Dumitru and R. D. Pisarski
	Testing the Polyakov Loop Model on the Lattice
	The Polyakov Loop Model makes testable predictions for the deconfined phase of QCD. In particular, the screening mass is related to the pressure.
	poster	Non-zero temperature and density
245	Pleiter, Dirk	dirk.pleiter@desy.de	top
	Dirk Pleiter
	Low-lying fermion modes of Nf=2 improved Wilson fermions
	We will present initial results for the topological charge and susceptibility determined from the low-lying eigenmodes of the Wilson-Dirac operator. These modes have been computed on dynamical configurations with Nf=2 non-perturbatively improved Wilson fermions. We compare our results with the eigenmodes of fermions in the quenched approximation.
	parallel talk	Topology and confinement   4
246	Polikarpov, Mikhail	polykarp@heron.itep.ru	top
	: V.G.Bornyakov, M.N.Chernodub, F.V.Gubarev, M.I.Polikarpov, T.Suzuki, A.I.Veselov, V.I.Zakharov
	Anatomy of the Magnetic Monopole in SU(2) Lattice Gauge Theory
	We study the Abelian and non-Abelian action density near the monopole in the maximal Abelian gauge of SU(2) lattice gauge theory. We find that the non-Abelian action density near the monopoles belonging to the percolating cluster decreases when we approach the monopole center. Our estimation for the monopole radius is R_mon ~ 0.06 fm
	poster	Topology and confinement
247	Pullirsch, Rainer	pull@kph.tuwien.ac.at	top
	B.A.Berg, U.M. Heller, H. Markum, R. Pullirsch, W. Sakuler
	Space-Time Correlations between Topological and Fermionic Densities in Compact QED
	To investigate the origin of the zero-modes of the overlap-Dirac operator in quenched compact QED we factorize the gauge configurations into monopole and photon fields. We find that the zero-modes lie solely in the monopole part of the gauge field and are completely absent in the photonic field. We pose the question of the existence of local correlations between the topological charge density and the monopole density. We are calculating spatial correlations with the wave functions related to fixed zero-mode number.
	poster	Topology and confinement
248	Rakow, Paul	rakow@ifh.de	top
	P.E.L. Rakow
	Separating perturbative and non-perturbative contributions to the plaquette
	There is a long history of trying to extract a non-perturbative gluon condensate from lattice calculations of the plaquette. Thanks to the work of Di Renzo at al. we have a much longer perturbation series for the plaquette than for any other lattice quantity. On the other hand, the plaquette is one of the most ultra-violet dominated quantities, which means that any non-perturbative contribution is likely to be very small compared with the perturbative part. We look at the large-n asymptotic behaviour of the perturbation series in order to estimate the order at which renormalon behaviour sets in, and to estimate the contribution of the as-yet unmeasured terms in the series. We compare tadpole improvement with other methods of accelerating the convergence of the series. Finally we reexamine the reported Lambda^2 contribution to the gluon condensate and attempt to determine the conventional Lambda^4 condensate.
	parallel talk	Topics in gauge theories   1
249	Rebbi, Claudio	rebbi@bu.edu	top
	L. Giusti, C. Hoelbling, C. Rebbi
	First results from quenched QCD simulations with overlap fermions.
	We present results for meson masses and decay constants obtained in quenched QCD with overlap fermions. We also discuss possible approximation techniques for the evaluation of the Dirac-Neuberger operator.
	parallel talk	QCD spectrum and quark masses   3
250	Reinhardt, Hugo	h.reinhardt@uni-tuebingen.de	top
	K. Langfeld, H. Reinhardt, J. Gattnar
	Manifestation of Confinement in the Gluon Propagator
	The gluon propagator of Su(2) Yang-Mills theory (YMT) is evaluated on the lattice in Landau gauge and in maximal center gauge (MCG). In both gauges the effect of center vortices on the gluon propagators is investigated. We find drastic changes when the confining center vortices are removed. The resulting gluon propagators are discussed in the context of the Kugo-Ojima confinement criterion and compared with the gluon propagator resulting from solving the gluon and ghost Schwinger-Dyson equations in continuum Yang-Mills theory.
	parallel talk	Topology and confinement   7
251	Reyes, Juan	Juan.Reyes@uv.es	top
	D. Becirevic, V. Gimenez, G. Martinelli and J. Reyes
	Combined Relativistic and static analysis for all \Delta B=2 operators at NLO.
	The b quarks are too heavy to be simulated on current lattices. One strategy adopted in this situation is to perform simulations with quark masses around the charm mass and then extrapolate to the physical b quark mass. We perform a combined analysis of APE relativistic data in the charm region and previous static results by matching all the dimension six \Delta B=2 operators in QCD with those in HQET at NLO order. The matrix elements of these operators are relevant for the prediction of the B-\bar B mixing, Bs meson width difference and supersymmetric effects in \Delta B=2 transitions. To do that we have to include the anomalous dimension matrix up to two loops, both in QCD and HQET, and the one loop matching for all the \Delta B=2 operators.
	parallel talk	Heavy quark physics   4
252	Rolf, Juri	rolf@physik.hu-berlin.de	top
	Juri Rolf, Stefan Sint
	Computation of the charm quark's mass in quenched QCD
	We determine the renormalization group invariant quark mass corresponding to the sum of the strange and the charm quark mass in the quenched approximation , using as essential input the mass of the D_s-meson. Since lattice artifacts turn out to be rather large we use O(a) improvement and take the continuum limit in the end.
	parallel talk	QCD spectrum and quark masses   3
253	Rossi, Giancarlo	gc.rossi@cern.ch	top
	L. Giusti, G.C. Rossi, M. Testa, G. Veneziano
	The $U_A(1)$ Problem on the Lattice
	In this talk I will show how it is possible to give a precise and unambiguous implementation of the Witten--Veneziano formula for the $\eta'$ mass in any regularized formulation of QCD. In general, counter-terms must be subtracted from the naive expression of the topological susceptibility. In the chiral limit their expression is fixed by anomalous flavour-singlet Ward--Takahashi identities, but depends on the particular regularization chosen for the fermions. No subtraction is needed for regularizations that satisfy the Ginsparg--Wilson relation. By using recent numerical results from simulations with overlap fermions in 2 (abelian Schwinger model) and 4 (QCD) dimensions, one obtains values for the mass of the lightest pseudo-scalar flavour-singlet state that agree within errors with theoretical expectations and experimental data, respectively.
	parallel talk	Theoretical developments   1
254	Rossi, Paolo	Paolo.Rossi@df.unipi.it	top
	Luigi Del Debbio, Haralambos Panagopoulos, Paolo Rossi And Ettore Vicari
	k-string tensions in SU(N) gauge theories
	In the context of SU(N) gauge theories we study the spectrum of the string tensions associated with different representations of the SU(N) group. We compute, for the 4d SU(6) gauge theory, the three independent string tensions in the k-rank antisymmetric representations using MC simulations in the Wilson lattice formulation. Our results support the sine formula for the ratio between the string tensions in the different representations, within an uncertainty of less than 2% for k=2 and 5% for k=3. The same formula has been derived in various realizations of SUSY SU(N) gauge theories. On the other hand our results do not support the hypothesis of Casimir scaling. We also comment on an analog behavior shown by the 2d SU(N)XSU(N) chiral models.
	parallel talk	Topology and confinement   5
255	Ryan, Sinead	ryan@maths.tcd.ie	top
	Sinead Ryan
	Heavy quark physics from lattice QCD
	[plenary talk]
	plenary talk
256	Saito, Takuya	tsaito@hiroshima-u.ac.jp	top
	T.Saito, A.Nakamura and S.Sakai
	Heavy quarks on the anisotropic lattice
	We compute the binding energies of the heavy quark system on the anisotropic lattice. We study dependence of the inconsistency for the binding energy reported by Collins et al.(hep-lat/9512026) and A.S.Kronfeld(hep-lat/9608139) on the anisotropy parameter $\xi$.
	poster	Heavy quark physics
257	Sakai, Sunao	eg110@kdeve.kj.yamagata-u.ac.jp	top
	S. Sakai, A. Nakamura and T. Saito
	Anisotropic Lattice and Its Application to Quark Gluon Plasma
	In the first parts of our poster, the effects of the self-energy term of the lattice potential on the anisotropy parameter is studied. It is found to be about 1% in the present range of beta and anisotropy. Then the anisotropy parameters are calculated in the smaller beta region by applying the Link integration method. It is found that it increases as beta becomes small for all improved actions studied in this work. In the latter part of our poster, we apply the anisotropic lattice to the calculation of the transport Coefficients of Quark Gluon Plasma. The preliminary results will be presented.
	poster	Non-zero temperature and density
258	Sasaki, Shoichi	ssasaki@phys.s.u-tokyo.ac.jp	top
	S.Sasaki, T.Blum and S.Ohta
	Nucleon axial charge from quenched lattice QCD with domain wall fermions and improved gauge action
	In our previous DWF calculation with Wilson gauge action at $\beta=6.0$ ($a^{-1}\simeq 1.9$ GeV) on a $16^3 \times 32 \times 16$ lattice, we found $G_A/G_V$ in the continuum limit had a fairly strong dependence on the quark mass. A simple linear extrapolation of $G_A$ to the chiral limit yielded a value that was a factor of two smaller than the experimental one. Here we report our recent study of this issue. In particular, we investigate possible errors arising from finite lattice volume, especially in the lighter quark mass region. We employ an RG-improved gauge action (DBW2) with ($a^{-1}=1.23$ GeV). We also investigate other possible sources of systematic errors such as quenching effects (for example quenched chiral logarithms, zero modes) through the axial Ward-Takahashi identity that governs $G_A$.
	parallel talk	Hadronic matrix elements   1
259	Schaefer, Stefan	stefan.schaefer@physik.uni-regensburg.de	top
	C. Gattringer, M. Goeckeler, C.B. Lang, P.E.L. Rakow, S. Schaefer and A. Schaefer
	A lattice study of the mechanism for chiral symmetry breaking
	We analyze spectra and localization properties of eigenvectors of the lattice Dirac operator as well as the local chirality of the near zero modes. We use two kinds of Dirac operators, the overlap operator and an approximate solution of the Ginsparg-Wilson equation. We study quenched ensembles generated at three different values of the gauge coupling and in addition perform an analysis of the volume dependence. Our observables support the mechanism for chiral symmetry breaking based on instantons.
	poster	Topology and confinement
260	Schierholz, Gerrit	Gerrit.Schierholz@desy.de	top
	G. Schierholz, for QCDSF and UKQCD
	Determination of the Lambda Parameter from quenched and N_f=2 dynamical QCD
	The scale parameter $\Lambda$ is computed on the lattice in the quenched approximation and for $N_f=2$ flavors of light dynamical quarks. The dynamical calculation is done with non-perturbatively $O(a)$ improved Wilson fermions.
	parallel talk	Hadronic matrix elements   2
261	Schiller, Arwed	schiller@itp.uni-leipzig.de	top
	M.N. Chernodub, E.-M. Ilgenfritz, A. Schiller
	Monopoles, confinement and deconfinement in lattice compact QED in $2+1 D$ with external fields
	We study the deconfinement phase transition and its relation to monopole properties in a lattice $3 D$ compact Abelian gauge model at $T>0$. Using a cluster analysis to separate single monopoles in vacuum from dipoles, we find the string tension to be in good agreement with semiclassical estimates based on the monopole density. In the deconfinement phase monopoles form a dilute gas of magnetic dipoles. Opposite to $3+1 D$ non-Abelian theory, external fields do not affect the confinement-deconfinement phase transition temperature but change the monopole content by creating additional dipoles from the vacuum. Contrary to the deconfinement phase, the non-vanishing internal field parallel to the external field is attenuated in the confinement phase. This screening becomes stronger with decreasing temperature.
	poster	Topology and confinement
262	Schilling, Klaus	schillin@theorie.physik.uni-wuppertal.de	top
	H. Neff, N. Eicker, Th. Lippert, J.N. Negele, and K. Schilling
	A new approach to eta´ on the lattice
	We demonstrate the viability of spectral approximations to ``disconnected´´ quark loops, as they appear e.g. in the hairpin diagram of the eta´ propagator. We show that the eta´-mass analysis can be substantially improved by ground state projecting the connected piece of its propagator.
	parallel talk	QCD spectrum and quark masses   2
263	Schlittgen, Boris	bozza@math.mit.edu	top
	Boris Schlittgen
	The Low-Energy Effective Theory of the Quantum Link Model
	The quantum link model provides an unconventional regularisation of gauge theory in which classical fields arise via dimensional reduction of discrete variables. This D-theory regularisation leads to the same continuum theory as the conventional approach. We show this by deriving the low-energy effective Lagrangian of the quantum link model using coherent state path integral techniques.
	parallel talk	Theoretical developments   2
264	Schmidt, Christian	schmidt@physik.uni-bielefeld.de	top
	F. Karsch, E. Laermann and Ch. Schmidt
	Universality at the chiral critical point of 3-flavour QCD
	We analyze the critical behaviour of 3-flavour QCD in the vicinity of the chiral critical point, i.e. the second order endpoint of a line of first order phase transitions. In order to find a mapping between 3-flavour QCD and the 3d Ising model we introduce linear combinations of the gluonic action and the chiral condensate. We consider these linear combinations as an approximation for the correct ordering-field as well as energy-like operators and discuss their fourth order cumulant and joint histogram for several mixing and mass parameters. Our results yield a location of the chiral critical point and supply evidence that for three flavours this point belongs to the universality class of the 3d Ising model. Using standard and improved staggered fermion actions we discuss the cut-off dependence of the critical point.
	parallel talk	Non-zero temperature and density   1
265	Schroers, Wolfram	Wolfram.Schroers@Feldtheorie.de	top
	et al
	The Quest for Light Fermions: Algorithms for the Future
	Results from a comparative study between multiboson algorithms and the widely-used HMC are presented. The tuning and optimization of multiboson algorithms are reviewed and the perspectives for future simulations are discussed. Requirements for future implementation systems are listed.
	parallel talk	Algorithms and machines   3
266	Schröder, York	york.schroder@helsinki.fi	top
	Y. Schröder (work in collaboration with K.Kajantie, M.Laine, K.Rummukainen)
	Resumming long-distance contributions to the QCD pressure
	The pressure (or free energy) of QCD is a most fundamental quantity, studied intensively with a variety of approaches. Lattice data is available at zero baryon density up to a few times the critical temperature $T_c$. Perturbation theory, even at very high temperatures, has serious convergence problems. Using a combined analytical and 3d lattice MC method, we show that it is possible to compute the QCD pressure from about $2 T_c$ to infinity in a well-defined framework.
	parallel talk	Non-zero temperature and density   7
267	Schulze, Thomas	tschulze@physik.uni-bielefeld.de	top
	J. Engels, S.Holtmann, T. Mendes, T.Schulze
	Comparison of finite-size-scaling functions for 3d O(N) spin models to QCD
	We calculate numerically universal finite-size-scaling functions of the magnetization for the three-dimensional O(4) and O(2) spin models. The approach of these functions to the infinite-volume scaling functions is studied in detail on the critical and pseudocritical lines. For this purpose we determine the pseudocritical line in two different ways. We find that the asymptotic form of the finite-size-scaling functions is already reached at small values of the scaling variable. A comparison with QCD lattice data for two flavours of staggered fermions shows a similar finite-size behaviour which is compatible with that of the spin models.
	parallel talk	Non-zero temperature and density   1
268	Scimia, Roberto	roberto.scimia@marconi.com	top
	G. Di Carlo, F. Palumbo, R. Scimia
	Larger physical volume with a noncompact lattice regularization
	We reconsider a noncompact regularization of gauge theories on a lattice where exact gauge invariance is enforced by means of auxiliary fields. This regularization was shown to give perturbative and numerical results in agreement with the Wilson theory. In its original formulation the theory was directly applicable only for the SU(2) gauge group. We performed a Monte Carlo simulation and obtained a physical volume larger than in Wilson regularization. We then extended the theory to the SU(n) case for arbitrary n in the hope of getting more reliable results in the physically interesting SU(3) case.
	parallel talk	Improvement and renormalization   4
269	Scorzato, Luigi	L.Scorzato@swansea.ac.uk	top
	Simon Hands, Istvan Montvay, Luigi Scorzato, Jonivar Skullerud
	Diquark condensation in dense SU2 matter
	We report on a lattice study of two-colour QCD with adjoint staggered fermions at high density. We find that the model has no early onset and we report on results for diquark condensation, from simulations with and without a diquark source term. We also comment on a preliminary study of two-colour QCD with two flavours of fundamental Wilson fermions.
	parallel talk	Non-zero temperature and density   3
270	Seefeld, Bernhard	seefeld@itp.unibe.ch	top
	M. Hasenbusch, P. Hasenfratz, F. Niedermayer, B. Seefeld, U. Wolff
	Nonstandard Cutoff Effects in the Nonlinear Sigma Model
	High precision measurements of the L\"uscher-Weisz-Wolff running coupling $\bar{g} = L \cdot M(L)$ and the renormalized coupling at zero-momentum $g_R$ performed with various lattice actions in the non-perturbative region confirm the earlier observations, that the cutoff effects look linear, in contrast to perturbative calculations. The use of different actions allows one to make a more reliable estimate on the continuum limit without explicit assumptions on the functional form of the lattice artifacts. The measurements were done for infinite volume correlation length up to 350.
	parallel talk	Spin models   2
271	Sharpe, Stephen	sharpe@phys.washington.edu	top
	Stephen Sharpe
	On-shell improved operators using unimproved correlators
	Recently, a method for O(a) improvement of composite operators has been proposed which uses the large momentum behavior of fixed gauge quark and gluon correlation functions (G. Martinelli et al, hep-lat/0106003). A practical problem with this method is that a particular improvement coefficient, c_NGI, which has a gauge non-covariant form, is difficult to determine. Here we argue that, with an appropriate choice of improvement conditions, one can determine all the physical, on-shell improvement coefficients for bilinear operators, despite not knowing the correct value of c_NGI.
	parallel talk	Improvement and renormalization   4
272	Shifman, Mikhail	shifman@physics.spa.umn.edu	top
	M. Shifman
	Lessons from supersymmetry for QCD
	Recently a few intriguing developments took place in supersymmetric gauge theories. It was argued that N vacua (N is the number of colors) of supersymmetric gluodynamics survive in the large N Yang-Mills theory (non-SUSY) in the form of quasistable states, with exponentially large life-times. In another development, supersymmetric gluodynamics was deformed (orbifolded) to produce a nonsupersymmetric descendant in such a way that certain miraculous degeneracies of SUSY are preserved. It is interesting to see whether these novel ideas can be tested on lattices.
	plenary talk
273	SHOJI, Fumiyoshi	shoji@riise.hiroshima-u.ac.jp	top
	F.Shoji
	Stochastic gauge fixing and gauge ambiguity
	We have reported new gauge fixing method for Abelian projection which is based on stochastic gauge fixing. In this method, it is expect that the global maximum is chosen on the gauge trajectory. In order to investigate the effectiveness to avoid Gribov copy, we compare our method with several methods with respect to the string tension in SU(2)QCD.
	poster	Topology and confinement
274	Simma, Hubert	simma@ifh.de	top
	H. Simma for the APE collaboration
	APEmille Parallel Computers
	We report on the progress and status of the installations of large APEmille systems at various European research institutions. Experiences with the operation of the machines in physics production runs and a summary of the results is presented.
	poster	Algorithms and machines
275	Simone, James	simone@fnal.gov	top
	J.N. Simone, S. Hashimoto, A.X. El-Khadra, A.S. Kronfeld, P.B. Mackenzie and S.M. Ryan
	The \BtoDstar\ Form Factor at Zero Recoil and the Determination of \Vcb
	We update Fermilab's calculation of the zero-recoil form factor, $F_{B\to D^*}(1)$, in \BtoDstar\ decays. In principle, our approach leads to a model independent determination of the $\mathcal{O}(1/m_Q^2)$ difference between $F_{B\to D^*}(1)$ and the form factor in the $m_b,m_c\to\infty$ limit. A model independent determination of the form factor promises to reduce the uncertainties in the extraction \Vcb\ which presently arise from quark model estimates of the $\mathcal{O}(1/m_Q^2)$ effects.
	parallel talk	Heavy quark physics   4
276	Sinclair, Donald	dks@hep.anl.gov	top
	D.K.Sinclair, J.B.Kogut
	Models at finite density and temperature.
	We are simulating 2-colour QCD at finite quark-number chemical potential and temperature, and true 3-colour QCD at finite isospin chemical potential, strangeness chemical potential and temperature. Particular emphasis is placed on the condensates formed and the accompanying Goldstone bosons.
	parallel talk	Non-zero temperature and density   3
277	Sint, Stefan	stefan.sint@cern.ch	top
	R. Frezzotti, S. Sint, P. Weisz
	O(a) improved twisted mass lattice QCD
	Lattice QCD with Wilson quarks and a chirally twisted mass term (tmQCD) represents an alternative regularization of QCD, which has been designed to eliminate unphysical fermion zero modes. Moreover, tmQCD allows to bypass certain lattice renormalization problems, and O(a) improvement can be applied in a straightforward manner. The structure of the O(a) improved theory is relatively simple and offers practical advantages over the standard framework, in particular concerning dynamical fermion simulations of QCD with two quark flavours.
	parallel talk	Improvement and renormalization   3
278	skullerud, jonivar	jonivar@mail.desy.de	top
	J.Skullerud, A.G.Williams
	The quark-gluon vertex in two momentum subtraction schemes
	We compute the quark-gluon vertex in quenched QCD, in the Landau gauge using an off-shell mean-field O(a)-improved fermion action. The running coupling is calculated in two different ("symmetric" and "asymmetric") momentum subtraction schemes.
	poster	Improvement and renormalization
279	So, Hiroto	so@muse.hep.sc.niigata-u.ac.jp	top
	K.Itoh, M.Kato, H.So, H.Sawanaka and N.Ukita
	Super Yang-Mills Theory on Lattice and the Transformation
	We propose new approach to super Yang-Mills Theory on lattice using 1-dimensional reduced models.
	parallel talk	Higgs Yukawa SUSY theories   1
280	Sodano, Pasquale	pasquale.sodano@pg.infn.it	top
	M.C.Diamantini, D. Marzoli, P.Sodano
	Strongly Coupled Massive QCD3 on the Lattice.
	Strongly coupled massive U(Nc) QED3 on a lattice is investigated using the 1/Nc expansion. We show that- for arbitrary number of fermion flavors Nf- the use of the strong coupling expansion yields a frustrated Heisenberg antiferromagnet as an effective model. For low Nf there are two phases exhibiting either Neel order or chiral spin order. For large Nf, with Nf/Nc of order 1, we evidence the disappearance of Neel order at a critical Nf. The relationship of this lattice model with Non Abelian Chern- Simons theory coupled with fermionic matter is discussed.
	parallel talk	Spin models   1
281	Sommer, Rainer	Rainer.Sommer@desy.de	top
	Jochen Heitger and Rainer Sommer
	A strategy to compute the b-quark mass with non-perturbative accuracy
	We describe a strategy to compute the b-quark mass to leading order in the Heavy Quark Effective Theory. The approach is fully non-perturbative. In particular it does not involve a perturbative subtraction of power law divergencies and the continuum limit may be taken. First numerical results in the quenched approximation demonstrate the potential of the method. In principle, the idea, based on non-perturbative matching in finite volume, may also be applied to the matching of composite operators or to Heavy Quark Effective Theory beyond the leading order.
	parallel talk	Heavy quark physics   1
282	soni, amarjit	soni@bnl.gov	top
	Amarjit Soni (RBC Collaboration)
	K to 2pi: Some implications of reported results and strategy for the immediate future.
	First lattice calculations using Domain Wall Quarks, in conjunction with lowest order chiral perturbation theory, have addressed the long standing issues pertaining to non-leptonic K decays. I will discuss some implications of these calculations and a rationale for chalking out strategy that should be followed bearing in mind existing proposals on K to 2 pi.
	poster	Hadronic matrix elements
283	Stamatescu, Ion-Olimpiu	stamates@thphys.uni-heidelberg.de	top
	G.Aarts, O.Kaczmarek, F.Karsch, I.-O.Stamatescu
	First order inverse mass corrections to quenched QCD at non-zero chemical potential
	We proceed from the formulation of quenched QCD at non-zero chemical potential realized as the double limit of large quark masses - large chemical potential. We perform simulations introducing first order (kappa squared) corrections to the above limit, to disentangle mass and chemical potential dependence. The sign problem is improved upon by using the center dependence of Polyakov loops. Results concerning the phase structure in the vicinity of the quenched limit with non-zero chemical potential at low and high temperatures are presented.
	parallel talk	Non-zero temperature and density   4
284	Stephanov, Misha	misha@uic.edu	top
	Novel Phenomena in Dense QCD
	New high density QCD phenomena will be described: asymptotic color deconfinement and metastable domain walls. Similar phenomena in isospin dense QCD could be studied on the lattice.
	parallel talk	Non-zero temperature and density   3
285	Streuer, Thomas	streuer@theorie.physik.uni-muenchen.de	top
	Thomas Streuer
	Monopoles in full QCD
	We study the dynamics of monopoles in the maximally abelian gauge in quenched and N_f=2 dynamical QCD using O(a) improved Wilson fermions. Significant differences between the quenched and the full theory are observed.
	parallel talk	Topology and confinement   8
286	Suganuma, Hideo	suganuma@th.phys.titech.ac.jp	top
	Hideo Suganuma, Hiroko Ichie, Noriyoshi Ishii, Kazuhisa Amemiya
	Strong Randomness of Off-diagonal Gluon Phases and Off-diagonal Gluon Mass in the MA Gauge in QCD
	We study Confinement Physics using lattice QCD. In the maximally abelian (MA) gauge, the off-diagonal gluon amplitude is strongly suppressed, and then the off-diagonal gluon phase shows strong randomness, which leads to a large effective off-diagonal gluon mass, $M_{\rm off} \simeq 1.2 {\rm GeV}$. Due to the large off-diagonal gluon mass in the MA gauge, infrared QCD is abelianized like nonabelian Higgs theories. In the MA gauge, there appears a macroscopic network of the monopole world-line covering the whole system. From the monopole current, we extract the dual gluon field $B_\mu$, and examine the longitudinal magnetic screening. We obtain $m_B \simeq$ 0.5 GeV in the infrared region, which indicates the dual Higgs mechanism by monopole condensation. From infrared abelian dominance and infrared monopole condensation, low-energy QCD in the MA gauge is described with the dual Ginzburg-Landau (DGL) theory.
	parallel talk	Topology and confinement   8
287	Suzuki, Tsuneo	suzuki@hep.s.kanazawa-u.ac.jp	top
	Tsuneo Suzuki Inst.Theor.Phys., Kanazawa Univ.,Japan
	Topics on monopole dynamics in gluodynamics
	Three topics on monopole dynamics in gluodynamics are presented. 1)Monopole effective action in the Laplacian gauge (S.Ito, T.W.Park, T.Suzuki): Monopole effective action in the Laplacian gauge is determined using an inverse MC method. Comparison with the MA gauge case is discussed. 2)The quantized dual abelian Higgs model derived from SU(2) gluodynamics and its vacuum structure (Y.Koma, E.-M.Ilgenfritz, M.I.Polikarpov, T.Suzuki): The dual abelian Higgs model (DAH) is derived numerically from SU(2) lattice gluodynamics. The color-electric flux-tube profile and the string tension are reproduced using MC simulations in the framework of DAH. 3)Lattice instanton action from 3D SU(2) Georgi-Glashow model (T.Yazawa, T.Suzuki): We study 3D Geogi-Glashow model on the lattice in London limit in an infrared region. After performing abelian projections in a unitary gauge and in a maximally abelian gauge, abelian and instanton dominances are observed and an effective instanton action is determined. We obtain an almost perfect instanton action for some regions of parameters in both gauges.
	poster	Topology and confinement
288	Söldner, Wolfgang	Wolfgang.Soeldner@physik.uni-regensburg.de	top
	M. Göckeler, P.E.L. Rakow, A. Schäfer, W. Söldner, T. Wettig
	Lattice QCD at finite temperature: evidence for calorons from the eigenvectors of the Dirac operator
	We analyze the eigenvalues and eigenvectors of the staggered Dirac operator in quenched lattice QCD in the vicinity of the deconfinement phase transition. The spectral and localization properties of the low lying eigenmodes show characteristic differences between the Z_3 sectors above the critical temperature T_c. These findings can be interpreted in terms of calorons.
	parallel talk	Non-zero temperature and density   6
289	Takaishi, Tetsuya	tt-taka@hue.ac.jp	top
	Tetsuya Takaishi
	Generalized ensemble algorithm for U(1) gauge theory
	Simulations of U(1) gauge theory near phase transition is difficult due to the appearance of metastable states. We use Tsallis weight instead of usual Boltzmann weight for the hybrid Monte Carlo and investigate whether we can overcome the difficulty.
	poster	Algorithms and machines
290	Taniguchi, Yusuke	tanigchi@het.ph.tsukuba.ac.jp	top
	CP-PACS Collaboration : S.Aoki, Y.Aoki, R.Burkhalter, S.Ejiri, M.Fukugita, S.Hashimoto, N.Ishizuka, Y.Iwasaki,T.Izubuchi, K.Kanaya, T.Kaneko, Y.Kuramashi, K.I.Nagai, V.Lesk, M.Okawa, Y.Taniguchi, A.Ukawa and T.Yoshi\'e
	Chiral property of domain-wall fermion from eigenvalue of 4D Wilson fermion Hamiltonian
	We investigate the chiral property of domain-wall fermion (DWF) from eigenvalues of the four dimensional Wilson fermion Hamiltonian. We discuss a formula which connects the residual mass $m_{5q}$ in the axial WT identity of DWF with eigenvalues of the 4D Wilson fermion Hamiltonian. This formula is tested for the DWF system with standard plaquette gauge action and renormalization group improved guge action at both strong and weak coupling region corresponding to the lattice spacing $a^{-1}\sim$ 1GeV and 2GeV. We study the behavior of the residual mass $m_{5q}$ at large fifth dimensional length through the eigenvalues. The question if chiral symmetry is realized in DWF for standard and improved action at strong and weak coupling region is discussed.
	parallel talk	Chiral fermions and gauge theories   1
291	Thacker, H. B.	hbt8r@virginia.edu	top
	H. Thacker, W. Bardeen, A. Duncan, E. Eichten, N. Isgur
	Quenched Chiral Loop Effects in the Scalar Propagator
	The scalar, isovector meson propagator is analyzed in quenched QCD. In addition to the expected short-range falloff characteristic of a heavy scalar meson, the propagator also exhibits a longer-range negative metric contribution which becomes pronounced for smaller quark masses. We show that this is a quenched chiral loop effect associated with the anomalous structure of the $\eta'$ propagator in quenched QCD.
	parallel talk	QCD spectrum and quark masses   4
292	Tomboulis, Terry E.	tombouli@physics.ucla.edu	top
	T. Kovacs and T. Tomboulis
	Twist eating and vortex gas
	We present estimates of free-energies with or without vortex-introducing twists by analytical variational, bond-moving decimation, and numerical methods. They give insight into the vortex picture of confinement, and the association or tagging of thick vortices by thin vortices as in gauge-fixing and center projection methods.
	parallel talk	Topology and confinement   7
293	Toussaint, Doug	doug@physics.arizona.edu	top
	Doug Toussaint
	Spectrum results with Kogut-Susskind quarks
	[plenary talk]
	plenary talk
294	Tripiccione, Raffaele	tripiccione@pi.infn.it	top
	Raffaele Tripiccione
	Status of APE
	[QCD machine report]
	plenary talk
295	Tsutsui, Naoto	naoto.tsutsui@kek.jp	top
	JLQCD collaboration: S. Aoki, R. Burkhalter, M. Fukugita, S. Hashimoto, K-I. Ishikawa, N. Ishizuka, Y. Iwasaki, K. Kanaya, T. Kaneko, Y. Kuramashi, M. Okawa, T. Onogi, S. Tominaga, N. Tsutsui, A. Ukawa, N. Yamada, T.~Yoshi\'{e}
	Heavy quark expansion parameters from lattice NRQCD
	Using the lattice NRQCD action for heavy quark, we calculate the heavy quark expansion parameters $\mu_{\pi}^2$ and $\mu_G^2$ for heavy-light mesons and heavy-light-light baryons, which appear in the heavy quark expansions of inclusive decay rates of $b$ hadrons. The results are compared with the HQET relations for mass differences among heavy hadrons.
	parallel talk	Heavy quark physics   3
296	Tucker, William	wwtucker@uiuc.edu	top
	William Tucker
	The Maximum Abelian Gauge in SU(3)
	Investigating Abelian and center dominance becomes more complicated when an SU(3) (as opposed to an SU(2)) gauge theory is involved. We gauge fix SU(3) configurations to the maximum Abelian gauge. We then project to get a U(1)XU(1) field. We find the potential V(R) from the U(1)XU(1). We then find the corresponding monopole distribution and calculate V(R) from this. We also perform an additional gauge fixing to the "indirect" maximum center gauge and calculate V(R) from the resulting vortices. All of these results are compared with the full SU(3) potential.
	poster	Topology and confinement
297	Ukawa, Akira	ukawa@rccp.tsukuba.ac.jp	top
	Akira Ukawa
	Cost of dynamical quark simulations
	[Panel statement]
	plenary talk
298	UMEDA, TAKASHI	tumeda@rccp.tsukuba.ac.jp	top
	H.~Matsufuru, T.~Onogi, T.~Umeda
	$O(a)$ improved Wilson quark action on anisotropic lattice
	The $O(a)$ improved Wilson quark action on the anisotropic lattice is investigated. We carry out numerical simulation in the quenched approximation, at three values of lattice spacing with the anisotropy $xi={a_\sigma}/{a_\tau}=4$, where $a_\sigma$ and $a_\tau$ are the spatial and the temporal lattice spacings, respectively. The renormalized anisotoropy is determined with the dispersion relation of mesons in the light quark region as well as around the charm quark mass. We discuss the systematic uncertainty due to the anisotropy and its effect on the light hadron spectrum.
	parallel talk	Improvement and renormalization   3
299	van Baal, Pierre	vanbaal@lorentz.leidenuniv.nl	top
	Pierre van Baal
	Abelian projected monopoles: to be or not to be
	The constituent monopoles that appear in the SU(3) caloron solution are studied by abelian projection through the Polyakov loop gauge. It follows that sometimes there are abelian projected monopoles, required by the non-trivial topology, that are not related to the actual constituent monopeles.
	parallel talk	Topology and confinement   7
300	Veselov, Alexander	veselov@heron.itep.ru	top
	E.-M. Ilgenfritz$^a$,B.V. Martemyanov$^b$,M. M\"uller-Preussker$^c$\\ and A. I. Veselov$^b$\\ $^a$ Institute of Theoretical Physics,\\ University of T\"ubingen, D-72076 T\"ubingen, Germany\\ $^b$ Institute for Theoretical and Experimental Physics
	Classical solutions with nontrivial holonomy boundary conditions in $SU(2)$ lattice gauge theory at $T \ne 0$
	We simulate $SU(2)$ lattice gauge fields at finite temperature with fixed holonomy values at the spatial boundary. We use standard cooling procedure to analyse the topological content. Different types of classical solutions with these boundary conditions are discovered: calorons composed from two half-integer topological charges (dyons) ($DD$) and objects composed from half-integer topological charges of opposite sign ($D\bar D$).We try to understand the structure of the thermal vacuum at $T < T_{deconf}$ in terms of these objects.
	poster	Topology and confinement
301	Vink, Jeroen	jcvink@science.uva.nl	top
	J.C.Vink (with J. Smit and M. Salle)
	Simulating Quantum Fields after a Quench
	We investigate (quantum) field dynamics after a sudden transition from the high temperature symmetric phase to a low temperature broken phase, a so-called quench. Before the quench the system is taken to be in its ground state. After the quench, the vacuum fluctuations augmented by the spinodal instability, develop into kink-like inhomogeneities. We discuss a new approach to supply the vacuum quantum fluctuations as initial conditions for subsequent classical field dynamics and compare it with the scheme used until now. Furthermore we use the recently developed Hartree ensemble method to simulate the quantum field dynamics after the quench.
	parallel talk	Non-zero temperature and density   7
302	Vranas, Pavlos	vranasp@us.ibm.com	top
	George Fleming and Pavlos Vranas
	Staggered domain wall fermions, Part II
	We present analytic results for free staggered domain wall fermions. We discuss the introduction of gauge fields and present numerical results for some simple interacting models.
	poster	Chiral fermions and gauge theories
303	Weigel, Martin	weigel@itp.uni-leipzig.de	top
	M. Weigel and W. Janke
	Vertex Models on Random Graphs
	A lattice discretization of the path-integral approach to the quantization of 2D gravity leads to the summation over so-called combinatorial triangulations resp. ``quadrangulations'', the dual lattices of which correspond to three-valent or four-valent planar random graphs, respectively. The ensemble of these graphs has a fractal structure with non-trivial Hausdorff dimension, which -- depending on the strength of the coupling between matter and gravitating space-time -- occasionally collapses into a set of minimally interacting subsystems, so-called ``baby universes''. These triangulations, however, naturally describe only the Euclidean sector of the theory, the possibility of a proper Wick-rotation back to the Lorentzian sector being unclear. As an approach in this direction, we consider vertex models coupled to $\phi^4$ gravity graphs as a means of a local distinction of time and space coordinates. Since an exact solution of this model is only partially possible, we investigate the problem via a Monte-Carlo simulation of the coupled system. A class of ergodic updates for four-valent random graphs is proposed in the spirit of the Pachner moves. For the vertex model part we use the loop algorithm, a non-local algorithm of the cluster-update type. In terms of statistical physics, the coupled system constitutes a model of annealed disorder with a rich phase structure. We present first results of the phase diagram of such a model and consider the possibility of ani nterpretation in terms of Lorentzian quantum gravity.
	poster	Quantum gravity and random surfaces
304	Wenger, Urs	wenger@thphys.ox.ac.uk	top
	UKQCD Collaboration: A. Borici, A.D. Kennedy, B. Pendleton, U. Wenger
	The overlap Dirac operator as a continued fraction
	We examine some properties of five dimensional formulations of the overlap Dirac operator using a continued fraction expansion. Within this formulation the inverse of the overlap operator can be calculated by a single Krylov space method. In addition, the equivalence class of a given continued fraction can be used to reduce the condition number of the resulting five dimensional linear system by two orders of magnitude. The method is illustrated on quenched gauge field configurations at \beta=5.9.
	parallel talk	Chiral fermions and gauge theories   3
305	Wettig, Tilo	tilo.wettig@yale.edu	top
	Tilo Wettig for the QCDOC collaboration
	The QCDOC project
	An overview is given of the QCDOC architecture, a massively parallel computer optimized for lattice QCD using system-on-a-chip technology. The heart of a single node is the PowerPC-based QCDOC ASIC, developed in collaboration with IBM Research. We describe in some detail the design of this ASIC, including the nearest-neighbor communications unit, as well as several of the hard- and software features unique to the QCDOC project.
	poster	Algorithms and machines
306	Wetzorke, Ines	wetzorke@physik.uni-bielefeld.de	top
	F. Karsch, E. Laermann, P. Petreczky, S. Stickan and I. Wetzorke
	Meson Spectral Functions at Finite Temperature
	We present first results for meson spectral functions at several temperatures below and above T_c. The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24-64)^3 x 16. The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature. Furthermore we study the influence of finite volume and cut-off effects on the correlation and spectral functions.
	parallel talk	Non-zero temperature and density   6
307	Wijewardhana, L.C.R.Wijewardhana	rohana@physics.uc.edu	top
	V.Miransky,G. Semenoff, I.Shovkovy and L.C.R.Wijewardhana
	Color Superconductivity in 2+1 dimensional Gauge Theories
	We analyze 2+1 dimensional gauge field theories at high fermion densities. Such gauge theory models have served as theoretical laboratories for analyzing theoretical issues relevant to four dimensions. We see that QCD in 2+1 dimensions exhibit color superconductivity. We see that for large chemical potentials the fermion pairing dynamics de couple from the infra red dynamics of the model. We also discuss how this formalism could be used to study the properties of planer condensed matter systems.
	parallel talk	Non-zero temperature and density   7
308	Wilcox, Walter	walter_wilcox@baylor.edu	top
	Walter Wilcox
	Heatbath Inversion of Lattice Operators
	The method of approximate inversion by heatbath, which can reduce Gaussian noise iterations by a factor of 2 to 3 compared to fully converged solutions, is studied for typical lattice operators.
	parallel talk	Algorithms and machines   2
309	Wilcox, Walter	walter_wilcox@baylor.edu	top
	Ronald Morgan, Walter Wilcox
	Deflated GMRES for Linear Equations in Lattice QCD
	Restarted GMRES is a method that has been used for solving the large systems of linear equations associated with QCD problems. We investigate improving the convergence by using a version of GMRES that deflated eigenvalues. This deflation is accomplished by including approximate eigenvectors in the Krylov subspaces for GMRES. This approach is particularly effective when there are multiple right-hand sides, because the information generated in solving the first right-hand side can be efficiently used for the subsequent right-hand sides. For problems with small eigenvalues, the rate of convergence can be more than twice as fast.
	poster	Algorithms and machines
310	Wingate, Matthew	wingate.9@osu.edu	top
	Heavy-light physics using NRQCD-staggered actions
	One leading source of uncertainty in the lattice computation of semi-leptonic form factors in B decay, and to a lesser extent B meson decay constants, comes from the extrapolation of the light quark mass to the physical up/down mass. This talk presents first explorations of simulating the light quark with improved staggered actions, which are free of the spurious zero modes that effect Wilson-like Dirac operators and are less costly. Methods for fitting to Euclidean-time NRQCD-staggered meson propagators are discussed, and some preliminary spectrum results are presented.
	parallel talk	Heavy quark physics   3
311	Wittig, Hartmut	wittig@amtp.liv.ac.uk	top
	P. Hernandez, K. Jansen, L. Lellouch and H. Wittig
	Non-perturbative renormalization of quark masses and the condensate for Ginsparg-Wilson fermions
	We present a method to compute non-perturbatively the renormalization constant of the scalar density for Ginsparg-Wilson fermions. It is based on a matching of renormalization group invariant masses at fixed pseudoscalar meson mass, making use of previous results obtained by the ALPHA Collaboration for O(a)-improved Wilson fermions. Our approach allows for the renormalization of scalar and pseudoscalar densities in lattice regularizations that preserve chiral symmetry and of quark masses in any regularization. As an application we compute the non-perturbative factor which relates the renormalization group invariant quark condensate to its bare counterpart, obtained with overlap fermions in the quenched approximation.
	parallel talk	Improvement and renormalization   1
312	Wittig, Hartmut	wittig@amtp.liv.ac.uk	top
	Hartmut Wittig
	Cost of dynamical quark simulations
	[Panel statement]
	plenary talk
313	Wolff, Ulli	uwolff@physik.hu-berlin.de	top
	Achim Bode, Roberto Frezzotti, Bernd Gehrmann, Martin Hasenbusch, Jochen Heitger, Karl Jansen, Stefan Kurth, Juri Rolf, Hubert Simma, Stefan Sint, Rainer Sommer, Peter Weisz, Hartmut Wittig and Ulli Wolff
	First results on the running coupling in QCD with two massless flavours
	We report on the non-perturbative computation of the running coupling of two-flavour QCD in the Schr"odinger functional scheme. The corresponding Lambda-parameter, which describes the coupling strength at high energy, is related to a low energy scale which still remains to be connected to a hadronic ``experimentally'' observable quantity. We find the *non-perturbative* evolution of the coupling indispensable to avoid untolerable errors in the estimated Lambda-parameter.
	parallel talk	Improvement and renormalization   2
314	Wosiek, Jacek	wosiek@th.if.uj.edu.pl	top
	P. Bialas and J. Wosiek
	Towards the lattice study of M-theory (II)
	Lattice discretization of the supersymmetric Yang-Mills quantum mechanics will be reviewed and the new results for D=4, N < 9, quenched system will be presented. The model, studied at finite temperature, reveals existence of the two distinct regions which may correspond to a black hole and elementary D0-branes phases of the M-theory conjectured in the literature. New results for higher gauge groups confirm this picture which was found earlier at N=2. Similar behaviour is observed in the preliminary simulations in D=6 and D=10 dimensions. The nature of the transition and its scaling with N is yet unresolved.
	parallel talk	Quantum gravity and random surfaces   1
315	Yaffe, Laurence	yaffe@phys.washington.edu	top
	Laurence Yaffe
	Real-time dynamics of hot gauge fields
	[plenary talk]
	plenary talk
316	Yamada, Norikazu	nyamada@suchi.kek.jp	top
	JLQCD collaboration: S. Aoki, R. Burkhalter, M. Fukugita, S. Hashimoto, K.-I. Ishikawa, N. Ishizuka, Y. Iwasaki, K. Kanaya, T. Kaneko, Y. Kuramashi, M. Okawa, T. Onogi, S. Tominaga, N. Tsutsui, A. Ukawa, N. Yamada, T. Yoshie
	B meson B-parameters with two-flavor dynamical QCD
	We present a full QCD calculation of B meson B-parameters with NRQCD heavy quark and non-perturbatively O(a)-improved Wilson light quark at $\beta=5.2$ on a $20^3\times 40$ lattice. We also report on a calculation of the $B$ meson decay constant. Sea quark effects on both quantities are examined.
	parallel talk	Heavy quark physics   4
317	Yamaguchi, Azusa	azusa@phys.columbia.edu	top
	A.Yamaguchi and Norman Christ
	Finite Baryon Number Simulations in the Static Limit
	We study finite temperture QCD with non-zero baryon number in the heavy quark limit, first investigated by Blum, Hetrick and Toussaint. In the simulations reported here we extend the work of those authors to larger volumes and lower baryon densities, examining both the character of the finite temperature phase transition and the increase in measurement errors with lattice volume.
	parallel talk	Non-zero temperature and density   4
318	Yamazaki, Takeshi	yamazaki@het.ph.tsukuba.ac.jp	top
	CP-PACS Collaboration : S.~Aoki, R.~Burkhalter, M.~Fukugita, S.~Hashimoto, N.~Ishizuka, Y.~Iwasaki, K.~Kanaya, T.~Kaneko, Y.~Kuramashi, V.~Lesk, M.~Okawa, Y.~Taniguchi, A.~Ukawa, T.~Yamazaki, T.~Yoshi\'e
	Maximum entropy analysis of hadron spectral funcions and excited states in quenched lattice QCD
	We apply the Maximum Entropy Method (MEM) to extract the spectral functions of Pseudo-Scalar and Vector mesons from propagator data previously calculated at four different lattice spacings in quenched QCD with the Wilson quark action. We determine masses and decay constants for ground and excited states from position and area of peaks in the spectral functions. Taking the continuum limit, we obtain $m_{\pi_1} = 662(593)$ MeV and $m_{\rho_1} = 1540(570)$ MeV for the first excited state masses within quneched QCD. We also find unphysical states, which have infinite mass in the continuum limit, and argue that they are bound states of two doublers of the Wilson quark action. If valid, this will be the first time that the state of doublers has been identified in lattice QCD numerical simulations.
	parallel talk	QCD spectrum and quark masses   2
319	Ying, He-Ping	hpying@cip-lx1.physik.uni-siegen.de	top
	H.P. Ying, J. Hu and L. Schuelke
	Critical Dynamics of Random-bond Potts Model with Continuous Self-dual Disorders
	We present Monte Carlo simulation results of random-bond Potts ferromagnet with the Continuous self-dual distribution of quenched disorders in two-dimensions [1]. By exploring the short-time scaling dynamics, we find universal power-law critical behavior of the magnetization and Binder cumulant at the critical point, and thus obtain estimates of the dynamic exponent $z$ and magnetic exponent $\eta$, as well as the exponent $\gth$. Our special attention is paid to the dynamic process for the $q$=8 Potts model following our previous work [2]. In detail we apply the STD approach [3] to the 2D RBPF with a continuous distribution of quenched disorders. Our simulations have verified that a second order phase transition has been induced. Then the universal dynamic scaling behavior in the short-time dynamics is used to estimate the exponents $\theta$ and $z$, as well the magnetic critical exponent $\eta$. It is found that they really violate the Ising-like universality class where $\theta=0.191(1)$ and $\eta=0.240(15)$ [4]. Our result of the dynamical exponent $z=3.41(6)$ is much bigger than that for systems without disorder, and it causes the microscopic time $t_{mic}$ to be extended up to one hundred for Binder cumulant from the ordered initial state. The value for the exponent $\eta$ nearly completely overlaps with all those obtained before, except that it is somewhat smaller (5\%) than that given in Ref.[1]. More accurate calculation remains to be done to solve this controversy. Our work is rather encouraging for the application of the short-time dynamic MC to simulate the scaling and critical dynamics of disordered spin systems. We will pursue this field in the future. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% References: [1] T. Olson and A. P. Young, Phys. Rev. B60, 3428(1999). [2] H.-P. Ying and K. Harada, Phys. Rev. E62, 174(2000). [3]B. Zheng, Int. J. Mod. Phys. B12, 1419(1998). [4]Z.B. Li, L. Schuelke, and B. Zheng, Phys. Rev. Lett. 74, 3396(1995); Phys. Rev. E53, 2940(1996).
	poster	Spin models
320	Yurishchev (Iourichtchev), Mikhail	yur@itp.ac.ru	top
	M.A.Yurishchev
	Self-Duality and Systems without Scaling Terms at Criticality
	It is argued that the self-duality of one system leads to the zero finite-size scaling amplitude of the critical internal energy for all isotropic models belonging to the same universality class. For such models, a condition of equality (up to corrections-to-scaling terms) of the internal energies for systems with different sizes can yield more accurate estimates for the critical temperature than a scaling equation for the inverse correlation lengths which is conventionally used in the phenomenological renormalization-group approach. Analytical and numerical evidences confirming the above supposition are done for the two-dimensional next-nearest-neighbour and spin-1 Ising models.
	poster	Spin models
321	Zubkov, Mikhail	naropa@orc.ru	top
	Polikarpov M.I. Veselov A.I. Zubkov M.A.
	Electroweak theory: the theta - term instead of the scalar field.
	We consider the SU(2)*U(1) lattice gauge model with the theta - term of the special type. We perform the numerical analysis and find the reasons to hope, that this theory is very close to the electroweak theory. The main feature of the model is the absence of the fundamental scalar field. The monopoles of the gauge theory play the role of the charged scalar particles.
	parallel talk	Topology and confinement   8
322	Zverev, Nikolai	zverev@physik.hu-berlin.de	top
	I. Bogolubsky, V. Mitrjushkin, I. Montvay, M. Mueller-Preussker, N. Zverev
	Performance Studies of the Two-Step Multiboson Algorithm in Compact Lattice QED
	The performance of the Two-step Multiboson (TSMB) algorithm is investigated in comparison with the Hybrid Monte-Carlo (HMC) method for compact lattice QED with standard Wilson fermions both in the Coulomb and Confinement phases. The restriction to QED allows for extensive measurements of autocorrelation times. Preliminary results show that the TSMB algorithm is at least competitive with standard HMC.
	parallel talk	Algorithms and machines   1
323	Zwanziger, Daniel	daniel.zwanziger	top
	Attilio Cucchieri and Daniel Zwanziger
	Gribov's theory of confinement: exact results in minimal Coulomb gauge
	In Gribov's scenario in Coulomb gauge, confinement of color charge is due to a long-range instantaneous color-Coulomb potential V(r), which is determined numerically from the instantaneous part of the gluon propagator D_{44,inst} = V(r)\delta(t). Confinement of gluons is reflected in the vanishing at k = 0 of the equal-time three-dimensionally transverse would-be physical gluon propagator D^{tr}(k). We present exact analytic results on D_{44} and D^{tr} (which have also been investigated numerically, A. Cucchieri, T. Mendes, and D. Zwanziger, this conference), in particular the vanishing of D^{tr}(k) at k = 0, and the determination of the running coupling constant from x_0g^2(k) = k^2 D_{44,inst}, where x_0 = 12N/(11N - 2N_f). We briefly indicate how these considerations extend to the Landau gauge, and how the Nielsen identities apply to gauges used in numerical gauge fixing.
	parallel talk	Topology and confinement   6

last modified: Thu Oct 18 16:43:31 2001 lattice2001@desy.de