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 ${\ensuremath{\pi}}^{0}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$, vanish in a chirally symmetric phase. Processes which are allowed, such as ${\ensuremath{\pi}}^{0}\ensuremath{\sigma}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$, are computed to leading order in a loop expansion.