Higgs-Yukawa physics on the lattice

Some selected publications

An invited review about chirally invariant Higgs-Yukawa models on the lattice
Higgs-Yukawa model in chirally-invariant lattice field theory
John Bulava, Philipp Gerhold, Karl Jansen, Jim Kallarackal, Bastian Knippschild, C.-J. David Lin, Kei-Ichi Nagai, Attila Nagy, Kenji Ogawa
Published in Adv.High Energy Phys. 2013 (2013) 875612
arXiv:1210.17980

An artickle that summarizes our work on chirally invariant Higgs Yukawa models

Figure: The phase structure analysis. The plot shows analytical predictions for the case of infinite volume, infinite number of flavours and small value of the quartic coupling. The black line indicates a first order phase transition, while all other transitions are of second order.


Abstract
Non-perturbative numerical lattice studies of the Higgs-Yukawa sector of the standard model with exact chiral symmetry are reviewed. In particular, we discuss bounds on the Higgs boson mass at the standard model top quark mass, and in the presence of heavy fermions. We present a comprehensive study of the phase structure of the theory at weak and very strong values of the Yukawa coupling as well as at non-zero temperature.

The effect of a hgher dimensional operator
A lattice study of a chirally invariant Higgs-Yukawa model including a higher dimensional Φ6-term
David Y.-J. Chu, Karl Jansen, Bastian Knippschild, C.-J. David Lin, Attila Nagy
Published in Phys.Lett.B 744 (2015) 146
arXiv:1501.05440

How does the phase diagram and Higgs mass bounds change in the presence of a higher dimensional operator?

Figure: The plot shows the constraint effective potential obtained by taking the logarithm of the histograms of the magnetization. The lines just serve to guide the eye.


Abstract
We discuss the non-thermal phase structure of a chirally invariant Higgs-Yukawa model on the lattice in the presence of a higher dimensional ΦΦ6-term. For the exploration of the phase diagram we use analytical, lattice perturbative calculations of the constraint effectice potential as well as numerical simulations. We also present first results of the effects of the Φ6-term on the lower Higgs boson mass bounds.

Upper Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa model

Philipp Gerhold and Karl Jansen
Published in JHEP 1004 (2010) 094
arXiv:1002.4336

Lower Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa model with overlap fermions

Philipp Gerhold and Karl Jansen
Published in JHEP 0907 (2009) 025
arXiv:0902.4135

Figure: The upper and lower Higgs boson mass bounds

These have been our works about Higgs boson mass bounds
We have computed the lower and upper Higgs boson mass bounds fully non-perturbatively in the Higgs-Yukawa sector of the standard model. In case, the Higgs boson is found, these bounds can serve to determine the energy scale up to which the standard model is valid.

Status of the finite temperature electroweak phase transition on the lattice

Karl Jansen
Published in Nucl.Phys.Proc.Suppl. 47 (1996) 196
hep-lat/9509018

This has been my first

Lattice Conference Plenary Talk

Figure: The finite temperature phase diagram

Content
This has been a review of the finite temperature electroweak phase transition. The graph shows that there is a only crossover for Higgs boson masses larger than about 80GeV. Therefore, the baryon asymmetry of the universe cannot be explained within the standard model. Also, the universe did not undergo any kind of electroweak (nor QCD) phase transition in its evolution, a fact, I find most remarkable, see this paper.

The triviality bound of the four component Phi**4 model

Anna Hasenfratz, Thomas Neuhaus, Karl Jansen, Christina Lang, Hiroshi Yoneyama
Published in Phys.Lett. B199 (1987) 531

This has been essentially the starting point for

my Ph.D. work

Figure: The upper Higgs boson mass bound in the O(4) symmetric scalar field theory

Content
The four-dimensional 0(4) Phi**4 scalar theory is investigated in the broken phase at different values of the quartic coupling lampda. The scalar mass, the field expectation value and the wave function renormalization constant are calculated. We demonstrate the lambda dependence of the ratio the Higgs boson mass to the renormalized vacuum expectation value estimate its upper bound to be around 2.7(1 ).

Phase structure of U(1) gauge-Higgs theory od d=4 lattices

Karl Jansen, Jiri Jersak, Christina Lang, Thomas Neuhaus, Gerald Vones
Published in Phys.Lett. B155 (1985) 268

This has been my

first publication ever

Figure: The phase diagram of a U(1) gauge Higgs model

Content
We describe a rich phase structure observed in Monte Carlo simulations of the d = 4 U(1) gauge-Higgs system on lattices up to size 8**4. The charge-one Higgs field has a dynamical radial degree of freedom. The phase transition between the Coulomb and the Higgs phases is of first order for small values of the quartic coupling lambda and weakens when either lambda or the inverse gauge field coupling beta increase. The confinement-Higgs transition approaches with decreasing lambda the two frustrations phases found for beta < -1 and might be analogous to a spin-glass transition.