Unambiguous test for the axion

Abstract

It is pointed out that a parallel search for the axion in the two decays $\frac{J}{\psi }\to \gamma +\mathrm{axion}$ and $\Upsilon \to \gamma +\mathrm{axion}$ is sufficient to either find the axion or to rule out its existence within the context of the standard model, independent of the free parameter in the theory. The required sensitivity is within experimental reach of existing and proposed experiments.