Anomalous mesonic interactions near a chiral phase transition

Abstract

Using constituent quarks coupled to a linear sigma model at nonzero temperature, I show that many anomalous mesonic amplitudes, such as $π^0 \rightarrow γγ$, vanish in a chirally symmetric phase. Processes which are allowed, such as $π^0 σ\rightarrow γγ$, are computed to leading order in a loop expansion.