Challenges for a QCD axion at the 10 MeV scale

A bstract We report on an interesting realization of the QCD axion, with mass in range $$ \mathcal{O} O (10) MeV. It has previously been shown that although this scenario is stringently constrained from multiple sources, model remains viable for a parameters leads to explanation Atomki experiment anomaly. In article we study more detail additional constraints proceeding recent low energy experiments and compatibility allowed parameter space one leading consistency most measurements electron anomalous magnetic moment fine structure constant. further provide ultraviolet completion axion variant show conditions under which it may lead observed quark masses CKM mixing angles, remain consistent experimental extended scalar sector appearing Standard Model extension. particular, decay Model-like Higgs boson into two light axions be relevant novel signature searched at LHC near future.