Chiral symmetry restoration and properties of Goldstone bosons at finite temperature

We study chiral symmetry restoration by analyzing thermal properties of QCD's（pseudo-） Goldstone bosons,especially the pion.The meson properties are obtained from the spectral densities of mesonic imaginary-time correlation functions.To obtain the correlation functions,we solve the Dyson-Schwinger equations and the inhomogeneous Bethe-Salpeter equations in the leading symmetry-preserving rainbow-ladder approximation.In chiral limit,the pion and its partner sigma degenerate at the critical temperature Tc.At T■Tc,it was found that the pion rapidly dissociates,which signals deconfinement phase transition.Beyond the chiral limit,the pion dissociation temperature can be used to define the pseudo-critical temperature of the chiral phase crossover,which is consistent with that obtained by the maximum point of chiral susceptibility.A parallel analysis for kaon and pseudo scalar ss suggests that heavy mesons may survive above Tc.