Search for the decay B0 --> J/psi gamma

TL;DR

This paper reports a search for the rare decay B0 --> J/psi gamma using data from the BABAR detector, setting an upper limit on its branching fraction due to no observed signal.

Contribution

First search for the B0 --> J/psi gamma decay, providing an upper limit on its branching fraction based on extensive data analysis.

Findings

No evidence for the decay was observed.

An upper limit of 1.6 x 10^-6 was set on the branching fraction.

The results constrain theoretical models predicting this decay.

Abstract

We present the results of a search for the radiative decay B0 --> J/psi gamma in a data set containing 123 million Y(4S)--> B B-bar decays, collected by the BABAR detector at the PEP-II asymmetric-energy e+e- storage ring at SLAC. We find no evidence for a signal and place an upper limit of B(B0 --> J/psi gamma) < 1.6 x 10^-6 at 90% confidence level.