Search for Rare and Forbidden 3-body Di-muon Decays of the Charmed Mesons D+ and Ds+

TL;DR

This paper reports a search for rare and forbidden three-body di-muon decays of D+ and Ds+ mesons using Fermilab data, setting new upper limits that constrain beyond Standard Model theories.

Contribution

First search for these specific rare decays with improved sensitivity, providing new upper limits that challenge certain supersymmetric models.

Findings

Upper limit for D+ > pion+ muon- muon+ is 8.8E-6 at 90% C.L.

Improved sensitivity by a factor of 1.7 to 14 over previous results.

Results constrain MSSM R-Parity violating models.

Abstract

Using a high statistics sample of photo-produced charm particles from the FOCUS experiment at Fermilab, we report results of a search for eight rare and Standard-Model-forbidden decays: D+, Ds+ > h+/- muon-/+ muon+ (with h=pion or Kaon). Improvement over previous results by a factor of 1.7--14 is realized. Our branching ratio upper limit D+ > pion+ muon- muon+ of 8.8E-6 at the 90% C.L. is below the current MSSM R-Parity violating constraint.