Search for the rare decays $B^{0}\to J/\psi \gamma$ and $B^{0}_{s} \to J/\psi \gamma$

TL;DR

This paper reports a search for rare B meson decays into J/psi and gamma, setting new upper limits on their branching fractions using LHCb data, with no significant signal observed.

Contribution

First experimental upper limits established for the branching fractions of B0s to J/psi gamma decays using LHCb data.

Findings

No significant signal observed for B0 and B0s decays.

Upper limits set at 1.7×10⁻⁶ for B0 and 7.4×10⁻⁶ for B0s.

First branching fraction limit for B0s to J/psi gamma decay.

Abstract

A search for the rare decay of a $B^{0}$ or $B^{0}_{s}$ meson into the final state $J/\psi\gamma$ is performed, using data collected by the LHCb experiment in $pp$ collisions at $\sqrt{s}=7$ and $8$ TeV, corresponding to an integrated luminosity of 3 fb$^{-1}$. The observed number of signal candidates is consistent with a background-only hypothesis. Branching fraction values larger than $1.7\times 10^{-6}$ for the $B^{0}\to J/\psi\gamma$ decay mode are excluded at 90% confidence level. For the $B^{0}_{s}\to J/\psi\gamma$ decay mode, branching fraction values larger than $7.4\times 10^{-6}$ are excluded at 90% confidence level, this is the first branching fraction limit for this decay.