Nonequilibrium meson production in strong fields

L Juchnowski ,Tobias Fischer ,D Blaschke ,S A Smolyansky

doi:10.1088/1742-6596/673/1/012009

Abstract

We develop a kinetic equation approach to nonequilibrium pion and sigma meson production in a time-dependent, chiral symmetry breaking field (inertial mechanism). We investigate the question to what extent the low-momentum pion enhancement observed in heavy- ion collisions at CERN - LHC can be addressed within this formalism. In a first step, we consider the inertial mechanism for nonequilibrium production of a—mesons and their simultaneous decay into pion pairs for two cases of a mass evolution. The resulting pion distribution shows a strong low-momentum enhancement which can be approximated by a thermal Bose distribution with a chemical potential that appears as a trace of the nonequilibrium process of its production.

Highlights

In the present work we develop the kinetic approach to nonequilibrium pion production in a time-dependent chiral symmetry breaking homogeneous field and investigate the question to what extent the low-momentum pion enhancement observed in heavy-ion collisions at CERN - LHC being discussed as Bose-Einstein condensation of pions [6] can be described within this formalism
In order to apply the inertial mechanism of meson production described by the coupled kinetic equations (3) and (5) to the case of heavy-ion collisions at LHC, we consider a scenario where the initial state is described by thermal equilibrium distributions of π and σ mesons with degenerate mass mπ(T0) = mσ(T0) = 140 MeV at T0 = Tc = 170 MeV
We have addressed the question to what extent the low-momentum pion enhancement observed in heavy-ion collisions at CERN - LHC being discussed as Bose-Einstein condensation of pions [5] can be described within this formalism

Summary

Introduction

In the present work we develop the kinetic approach to nonequilibrium pion production in a time-dependent chiral symmetry breaking homogeneous field and investigate the question to what extent the low-momentum pion enhancement observed in heavy-ion collisions at CERN - LHC being discussed as Bose-Einstein condensation of pions [6] can be described within this formalism. To this end we set up a detailed study of the three main processes that are intertwined in this case: (a) the nonequilibrium σ−meson production in the time-dependent external field, (b) the σ → ππ decay and (c) the ππ rescattering and formation of the Bose condensate [7, 8].

Results

Conclusion