SCREENING MASS FROM CHIRAL PERTURBATION-THEORY, VIRIAL EXPANSION, ANDTHE LATTICE

We calculate the electric screening mass in hot hadronic matter using two different approaches, chiral perturbation theory and the relativis tic virial expansion with empirical phase shifts, and compare the resu lts to each other and to a gas of free pions and rho mesons. We also c ompute the electric screening mass for noninteracting, charged bosons with mass m on a lattice to study likely finite-size effects in lattic e gauge theory simulations of continuum QCD. For a lattice of given si ze, the continuum can be properly represented only for a window in the ratio T/m.