A search for the rare decay of a B0 or Bs0 meson into the final state J/ψγ is performed, using data collected by the LHCb experiment in pp collisions at 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 1.5×10-6 for the B0→J/ψγ decay mode are excluded at 90% confidence level. For the Bs0→J/ψγ decay mode, branching fraction values larger than 7.3×10-6 are excluded at 90% confidence level; this is the first branching fraction limit for this decay.
Aaij, R., Abellán Beteta, C., Adeva, B., Adinolfi, M., Affolder, A., Ajaltouni, Z., … Zucchelli, S. (2015). Search for the rare decays B0 →j /ψγ and Bs0 →j /ψγ. Physical Review D - Particles, Fields, Gravitation and Cosmology, 92(11). https://doi.org/10.1103/PhysRevD.92.112002