Searches for Rare and Forbidden Decays of Charm: Recent Results from FNAL

TL;DR

This paper reviews experimental searches for rare and forbidden charm meson decays at FNAL, setting upper limits on their branching fractions to constrain theories beyond the Standard Model.

Contribution

It provides new upper limits on branching fractions for numerous decay modes, enhancing constraints on new physics models.

Findings

No evidence of rare or forbidden decays observed.

Upper limits set on branching fractions for over two dozen decay modes.

Results help constrain extensions to the Standard Model.

Abstract

We review results on rare and forbidden decays of D^0, D^+, and D^+_s mesons from experiments at FNAL. The decay modes studied have two leptons in the final state and, if observed, would constitute evidence for flavor-changing neutral-current, lepton-flavor-violating, or lepton-number-violating processes. To date, no evidence for these decays has been observed and upper limits are obtained for their branching fractions. These limits can constrain various extensions to the Standard Model. We present new upper limits from FNAL E791 on the branching fractions for more than two dozen three- and four-body decay modes.