Rare and Forbidden Decays of D Mesons

TL;DR

This paper reports on searches for rare and forbidden decays of D mesons involving leptons, setting new upper limits on their branching fractions and improving previous constraints.

Contribution

It provides the first limits for 26 decay modes and significantly improves constraints for 18 others, advancing the search for new physics in charm meson decays.

Findings

No evidence for the targeted rare decays was observed.

Established upper limits for 51 decay modes at 90% confidence level.

Improved constraints for 18 previously studied decay modes.

Abstract

We summarize the results of two recent searches 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 examined D+ and Ds pi,l,l and K,l,l decay modes and the D0 dilepton decay modes containing either l+,l-, a rho0, K*0, or phi vector meson, or a non-resonant pi,pi, K,pi, or K,K pair of pseudoscalar mesons. No evidence for any of these decays was found. Therefore, we presented branching-fraction upper limits at 90% confidence level for the 51 decay modes examined. Twenty-six of these modes had no previously reported limits, and eighteen of the remainder were reported with significant improvements over previously published results.