In a hot, chirally symmetric phase, ${\pi }^0$ doesn't go into $2\gamma$, but ${\pi }^0\sigma$ does

Abstract

In a constituent quark model at nonzero temperature, the amplitude for ${\pi }^0\to 2\gamma$ vanishes in a chirally symmetric phase, while that for ${\pi }^0\sigma \to 2\gamma$ does not.

Comments: 7 pages, LaTeX. To appear in: "From thermal field theory to neural networks, a day to remember Tanguy Altherr", World Scientific Publishing