Abstract
A study of the decays B^0_s rightarrow mu ^+mu ^- and B^0 rightarrow mu ^+mu ^- has been performed using data corresponding to an integrated luminosity of 25 fb^{-1} of 7 and 8 TeV proton–proton 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 mathcal{B}(B^0 rightarrow mu ^+mu ^-) < 4.2 times 10^{-10} at 95 % confidence level. For B^0_s, the branching fraction mathcal{B}(B^0_s rightarrow mu ^+mu ^-) = left( 0.9^{+1.1}_{-0.8} right) times 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.
Highlights
Flavour-changing neutral-current (FCNC) processes are highly suppressed in the Standard Model (SM), and their study is relevant to indirect searches for physics beyond the SM
This paper reports the result of a search for Bs0 → μ+μ− and B0 → μ+μ− decays performed using pp collision data corresponding to an integrated luminosity of 25 fb−1, collected at 7 and 8 TeV in the full LHC Run 1 data-taking period e-mail: atlas.publications@cern.ch using the ATLAS detector
11.3 Results of the signal yield extraction. Including both the 2012 and 2011 data-taking periods, the numbers of background events contained in the signal region (5166–5526 MeV) are computed from the interpolation of the data observed in the sidebands
Summary
Flavour-changing neutral-current (FCNC) processes are highly suppressed in the Standard Model (SM), and their study is relevant to indirect searches for physics beyond the SM. The branching fractions of the decays B0(s) → μ+μ− are of particular interest because of the additional helicity suppression and since they are accurately predicted in the SM: B(Bs0 → μ+μ−) = (3.65 ± 0.23) × 10−9 and B(B0 → μ+μ−) = (1.06 ± 0.09) × 10−10 [1]. Significant deviations from these values can arise in models involving non-SM heavy particles, such as those predicted in the Minimal Supersymmetric Standard Model [2,3,4,5,6], in extensions such as Minimal Flavour Violation [7,8], TwoHiggs-Doublet Models [6], and others [9,10].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
