par Chatrchyan, Serguei;Caillol, Cécile ;Clerbaux, Barbara ;De Lentdecker, Gilles ;Favart, Laurent ;Gay, Arnaud ;Hreus, Tomas ;Leonard, Alexandre ;Marage, Pierre ;Mohammadi, Abdollah ;Pernie, Luca ;Reis, Thomas ;Seva, Tomislav ;Thomas, Laurent ;Vander Velde, Catherine ;Vanlaer, Pascal ;Wang, Jian ; [et al.]
Référence Physical Review Letters, 111, 10, 101804
Publication Publié, 2013
Référence Physical Review Letters, 111, 10, 101804
Publication Publié, 2013
Article révisé par les pairs
Résumé : | Results are presented from a search for the rare decays Bs0→μ+μ- and B0→μ+μ - in pp collisions at √s=7 and 8 TeV, with data samples corresponding to integrated luminosities of 5 and 20 fb-1, respectively, collected by the CMS experiment at the LHC. An unbinned maximum-likelihood fit to the dimuon invariant mass distribution gives a branching fraction B(Bs0→μ+μ-)=(3.0-0.9+1.0) ×10-9, where the uncertainty includes both statistical and systematic contributions. An excess of Bs0→μ+μ- events with respect to background is observed with a significance of 4.3 standard deviations. For the decay B0→μ+μ- an upper limit of B(B0→μ+μ-)<1.1×10 -9 at the 95% confidence level is determined. Both results are in agreement with the expectations from the standard model. |