PION POLARIZABILITIES IN HOT MEDIUM

The pion polarisability is investigated in the Nambu-Jona-Lasinio mode l at finite temperature. The quark and pion loops, scalar and vector i ntermediate resonanses were considered. We have shown that the polariz abilities of charge and neutral pions have a very different behavior n ear the critical temperature if we consider the Compton effect off the pion. The charged pion polarizability is positive, decreases very qui ckly in the region where T > 200MeV and has no contributiolls from mes on clouds. The neutral pion polarizability is negative and monotonical ly increases in absolute value with T together with contributions of p ion clouds.