Rare and Forbidden Decays Analyses Memos

We report the results of a search for flavor-changing neutral-current (FCNC), lepton number violating (LNV) and lepton family violating (LFV) decays of , and (and their antiparticles) into modes containing muons and electrons. The results come from Fermilab charm hadroproduction experiment E791. For we examined the decay modes and . For we examined the decay modes and . For we examined the decay modes . We present upper limits on the branching fractions at the 90% confidence level. These upper limits provide significant improvements over published results.

We report the results of a search for flavor-changing neutral-current (FCNC), lepton family violating (LFV) decays, and lepton number violating (LNV) decays of the 4-particle decay modes of (and their antiparticles) into modes containing muons and electrons. The results come from Fermilab charm hadroproduction experiment E791. We examined the resonant decay modes , , and as well as the , , and (both the opposite-sign and same-sign dileptons) decay modes. We present upper limits on the branching fractions at the 90% confidence level. These upper limits provide significant improvements over published results.