2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/46489At finite temperature, the Nambu-Goldstone bosons of a spontaneously broken chiral symmetry travel at a velocity $v < 1$. This effect first appears at order $\sim T^4$ in an expansion about low temperature, and can be related to the appearence of two distinct pion decay constants in a thermal bath. We discuss some consequences on the thermodynamics of a gas of massless pions.5 pages, 1 figure. Talk given at the "Rhic Summer Studies '96", Brookhaven National Laboratory, Upton, USA. July 96High Energy Physics - PhenomenologyNuclear Theorytext