Observation of the Decay $K_L\to {\mu }^{+}{\mu }^{-}\gamma \gamma$

A. Alavi-Harati

We have observed the decay $K_L\to {\mu }^{+}{\mu }^{-}\gamma \gamma$ at the KTeV experiment at Fermilab. This decay presents a formidable background to the search for new physics in $K_L\to {\pi }^0{\mu }^{+}{\mu }^{-}$. Th…