KL→γγ: Theory and phenomenology

Abstract

We compute the one-loop quark-diagram contribution to $d\overline{s}\to \gamma \gamma$ in the standard model as a function of $m_q$ where $q=u,c,t,\mathrm{etc}$. We find it to be bounded, and such that the process $K_L\to \gamma \gamma$ is likely to be dominated by low-energy contributions. We then use a phenomenological pole-dominance model to obtain $\left|\frac{A_{\mathrm{theory}}}{A_{\mathrm{experiment}}}\right|=1.0\mathrm{}\pm 0.3$.