Chiral symmetry breaking and chemical equilibrium in heavy-ion collisions

We examine the thermalization of an ensemble octet pseudoscalar mesons, in isospin symmetric limit, whose interactions are constrained through chiral symmetry, unitarity, and measurements. use unitarized reaction amplitudes from next-to-leading-order perturbation theory which generate all resonances up to masses about 2 GeV, with 12 input parameters, namely, ${f}_{\ensuremath{\pi}}$, three masses, eight low-energy constants theory. In linear response theory, we find that relaxation time is around 100 fm at a temperature 150 MeV increases rapidly temperature. The long times directly related fact these mesons pseudo-Goldstone bosons symmetry breaking.