Electromagnetic axial anomaly in a generalized linear sigma model

Abstract

We construct the electromagnetic anomaly effective term for a generalized linear sigma model with two chiral nonets, one with a quark-antiquark structure, the other one with a four quark content. We compute in the leading order of this framework the decays into two photons of six pseudoscalars: $\pi_0(137)$, $\pi_0(1300)$, $\eta(547)$, $\eta(958)$, $\eta(1295)$ and $\eta(1760)$. Our results agree well with the available experimental data.