An Objective analysis package and the search for Lambda_c at H1

Paper: 325
Session: A (talk)
Speaker: Rouse, Forest, University of California, Davis
Keywords: analysis, C++, object-oriented methods

An Objective analysis package and the search for Lambda_c at

Forest Rouse
University of California, Davis


This paper describes the status of the search for the Lambda_c in
Deep Inelastic 1994 data sample at H1 using an portable objective
analysis package. We searched for Lambda_c
decays into 3 separate
decay modes:
Lambda_c ->p K0
Lambda_c ->Lambda pi
Lambda_c ->Lambda pi pi pi .
We find a clear signal in the p K0 and Lambda pi

The novel software technique allows the user
to specify the final states of interest and the cuts on those final
states. For instance, if the user specifies D0 as the final state of
interest, the software will search for given decay modes of the D0.
The software determines the invariant mass of the decay products
forming the final state candidate, vertexs the decay products,
propagates the tracking errors. Cuts can be placed on all of the
physics quantities formed. Users can modify the existing default cuts
or place different cuts based on the final state being searched for.
For instance, K0 vertex or decay cuts can be different from
Lambda vertex or decay cuts.

The heart of the kinematic fitting is much like SQUAW.
The novelty of the software comes from it's ability to
recursively search for final states.
Also, unlike SQUAW, any one track can be used in any number of
final state candidates. The software also can be ported to different
experiments. Finally, a user needs about 20 lines of FORTRAN
subroutines to use the system. The system is itself written in C++.

This paper describes the package and some of the lessons learned in
how objective analysis can be used to analyze high energy physics data.