Short-lived axions and kaon decay

Abstract

An experimental limit for the branching ratio $\frac{\Gamma (K^{+}\to {\pi }^{+}a)}{\Gamma (K^{+}}\to \mathrm{all})\le 1.5\times {10}^{-5\mathrm{}}$, where $a$ is a light, short-lived axion that decays via $a\to e^{+}e$, is presented.