Study of the rare decays of B⁰ₛ B s 0 and B⁰ B 0 into muon pairs from data collected during the LHC Run 1 with the ATLAS detector

A study of the decays B 0 s + -and B 0 + -has been performed using data corresponding to an integrated luminosity of 25 fb -1 of 7 and 8 TeV protonproton collisions collected with the ATLAS detector during the LHC Run 1. For the B 0 dimuon decay, an upper limit on the branching fraction is set at B(B 0 + -) < 4.2 10 -10 at 95 % confidence level. For B 0 s , the branching fraction B(B 0 s + -) = 0.9 +1.1 -0.8 10 -9 is measured. The results are consistent with the Standard Model expectation with a p value of 4.8 %, corresponding to 2.0 standard deviations.