Axion production in the $\eta \to \pi \pi a$ decay within $SU(3)$ chiral perturbation theory

Jin-Bao Wang, Zhi-Hui Guo, Zhun Lu +1

We study the axion and axion-like particle production from the $\eta \to \pi \pi a$ decay within the $SU(3)$ chiral perturbation theory up to the one-loop level. The conventional $SU(3)$ chir…