Masses of vector and axial-vector mesons at finite temperature

The temperature dependence of the effective masses of vector mesons ($\rho$ and $\omega$) and axialvector mesons ($A_1$) are examined with the use of an effective chiral Lagrangian. The effective masses at finite temperature are determined from the pole positions of the propagators and from the inverses of the static screening lengths. The results may be viewed as an extrapolation of known hadronic interactions to temperatures up to a deconfinement/chiral-symmetry-restoring transition or crossover.