Search for Lepton-number-violating B+->D-l+l'+ Decays

TL;DR

This study conducted the first search for lepton-number-violating B+ decays into D- and same-sign leptons, setting new upper limits on their branching fractions using a large data sample from the Belle detector.

Contribution

It provides the first experimental search for specific lepton-number-violating B+ decays and establishes upper limits on their branching fractions.

Findings

No evidence for the decays was observed.

Upper limits on branching fractions were set at 90% confidence level.

The results constrain models predicting lepton-number violation in B+ decays.

Abstract

We perform the first search for lepton-number-violating B+->D-l+l'+ decays, where l and l' stand for e or mu, using 772 x 10^6 BB-bar pairs accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB e^+e^- collider. No evidence for these decays has been found. Assuming uniform three-body phase space distributions for the D-l+l+ decays, we set the following upper limits on the branching fractions at 90% confidence level: Br(B+ -> D-e+e+) < 2.6x10^-6, Br(B+ -> D-e+mu+) < 1.8x10^-6 and Br(B+ -> D-mu+mu+) < 1.0x10^-6.