CHIRAL THERMODYNAMICS IN THE 1/N EXPANSION

We calculate the partition function of the O(4) nonlinear sigma-model with explicit symmetry breaking to lowest order in 1/N(N=4). Fixing the parameters at temperature T=0 to reproduce the observed pion mass m(pi) and the pion decay constant f(pi) we calculate the pressure, the energy density and entropy density as a function of the temperature. With PCAC we also determine the order parameter [qq(T)BAR] of chiral symmetry breaking. At low temperatures T< 100 MeV our results coincide with those obtained in chiral perturbation theory in the three loop approximation.