Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Distribution of Neutral and Charged Pions through the Production
  of a Classical Pion Field   High energy reactions may produce a state around the collision point that is
best described by a classical pion field. Such a field might be an isospin
rotated vacuum of the chiral $\sigma$-model or, as discussed in this work, a
solution of the equations of motion resultinng from the coupling of fields of
this model to quarks produced in the collision. In such configurations all
directions in isospin space are allowed leading to a sizable probability of
events with, essentially, only charged particles (Centauros) or all neutral
particles (anti-Centauros). (In more common statistical models of multiparticle
production, the probability of such events is suppressed exponentially by the
total multiplicity.) We find that the isospin violation due to the mass
difference of the up and down quarks has a significant effect on these
distributions and enhances the production of events consisting predominantly of
neutral particles.

37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph