Search for Rare and Forbidden Dilepton Decays of the D+, Ds, and D0 Charmed Mesons

TL;DR

This study searched for rare and forbidden decays of D and D_s mesons involving leptons, setting new upper limits on their branching fractions due to no observed signals.

Contribution

It provides the first limits for eight decay modes and improves existing limits for fourteen others in the search for new physics in charm meson decays.

Findings

No evidence for the targeted decays was observed.

Established upper limits for 24 decay modes at 90% confidence level.

Eight decay modes had no previous experimental limits.

Abstract

We report the results of a search for flavor-changing neutral current, lepton-flavor violating, and lepton-number violating decays of D+, Ds, and D0 mesons (and their antiparticles) into modes containing muons and electrons. Using data from Fermilab charm hadroproduction experiment E791, we examine the pi,l,l and K,l,l decay modes of D+ and Ds and the l+l- decay modes of D0. No evidence for any of these decays is found. Therefore, we present branching-fraction upper limits at 90% confidence level for the 24 decay modes examined. Eight of these modes have no previously reported limits, and fourteen are reported with significant improvements over previously published results.