Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Chemical equilibrium study in nucleus-nucleus collisions at relativistic
  energies   We present a detailed study of chemical freeze-out in nucleus-nucleus
collisions at beam energies of 11.6, 30, 40, 80 and 158A GeV. By analyzing
hadronic multiplicities within the statistical hadronization approach, we have
studied the strangeness production as a function of centre of mass energy and
of the parameters of the source. We have tested and compared different versions
of the statistical model, with special emphasis on possible explanations of the
observed strangeness hadronic phase space under-saturation. We show that, in
this energy range, the use of hadron yields at midrapidity instead of in full
phase space artificially enhances strangeness production and could lead to
incorrect conclusions as far as the occurrence of full chemical equilibrium is
concerned. In addition to the basic model with an extra strange quark
non-equilibrium parameter, we have tested three more schemes: a two-component
model superimposing hadrons coming out of single nucleon-nucleon interactions
to those emerging from large fireballs at equilibrium, a model with local
strangeness neutrality and a model with strange and light quark non-equilibrium
parameters. The behaviour of the source parameters as a function of colliding
system and collision energy is studied. The description of strangeness
production entails a non-monotonic energy dependence of strangeness saturation
parameter gamma_S with a maximum around 30A GeV. We also present predictions of
the production rates of still unmeasured hadrons including the newly discovered
Theta^+(1540) pentaquark baryon.

6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat