$K_L\text{ra}{\mu }^{\pm }{e}^{\mp }\nu \overline{\nu }$ as background to $K_L\text{ra}{\mu }^{\pm }{e}^{\mp }$

Abstract

We consider the process $K_L\text{ra}{\mu }^{\pm }{e}^{\mp }\nu \overline{\nu }$ at next to leading order in chiral perturbation theory. This process occurs in the standard model at second order in the weak interaction and constitutes a potential background in searches for new physics through the modes $K_L\text{ra}{\mu }^{\pm }{e}^{\mp }$. We find that the same cut, $M_{\mu e}>489$~MeV, used to remove the sequential decays $K_{l3}\text{ra}{\pi }_{l2}$ pushes the $B(K_L\text{ra}{\mu }^{\pm }{e}^{\mp }\nu \overline{\nu })$ to the $10^{-23}$ level, effectively removing it as a background.

Comments: 8 pages, LaTeX, 1 figure appended as postscript file after \end{document}. Fermilab-Pub-93/024-T