Axion-meson mixing in light of recent lattice $\eta$-${\eta }^{\prime }$ simulations and their two-photon couplings within $U(3)$ chiral theory

Rui Gao, Zhi-Hui Guo, J. A. Oller +1

We study the mixing of the QCD/QCD-like axion and light-flavor mesons ${\pi }^0,\eta ,{\eta }^{\prime }$ within the framework of $U(3)$ chiral perturbation theory up to next-to-leading order in this wor…