Search for KL0'e and KL0'ee decays

Abstract

We report on the present status of a search for the rare decays KL0'e and KL0'ee at the KEK 12-GeV Proton Synchrotron. We found no KL0'e or KL0'ee events and found 54 KL0' events. The upper limits of the KL0'e and KL0'ee branching ratios are B(KL0'e)<4.3×10-10 and B(KL0'ee)<5.6×10-10 at 90% confidence level. The 54 KL0' events correspond to an absolute branching ratio of (8.41.1)×10-9. © 1989 The American Physical Society.