Study of B0 --> l+l'- decays (l,l' = e,mu)

TL;DR

This study searches for rare B0 meson decays into lepton pairs using BABAR data but finds no evidence, setting upper limits on their branching fractions to constrain new physics models.

Contribution

First search for B0 --> e+e-, mu+ mu-, and e mu decays with a large dataset, establishing new upper limits on their branching fractions.

Findings

No evidence for the decay modes was observed.

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

Results constrain theories predicting these rare decays.

Abstract

We present a search for the decays B0 --> e+e-, B0 --> mu+ mu- and B0 --> e mu using data collected with the BABAR detector at the PEP-II e+e-collider at SLAC. Using a dataset corresponding to 384 x 10^6 BBbar pairs, we do not find evidence of any of the three decay modes. We obtain upper limit on the branching fractions, at 90% confidence level, of B(B0 --> e+e-)< 11.3 x 10^{-8}, B(B0 --> mu+ mu-) < 5.2 x 10^{-8}, and B(B0 --> e mu) < 9.2 x 10^{-8}.