A search for the rare decay B+->Lambda-pmu+mu- is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of sqrt(s)=13 TeV, corresponding to an integrated luminosity of 5.4 fb-1. An excess of events is found with respect to the background-only expectation, with a signal significance of 3.5 standard deviations, in the low invariant-mass region of m(antiLambda p)<2.8 GeV/c2. The branching fraction is measured to be B_{low}(B+ ->antiLambda pmu+mu-) =(1.70-0.56+0.65(stat)\pm0.17(syst)\pm0.14(ext))x10-8, where the last uncertainty is due to external inputs on B(B+->J/Psi antiΛ p)xB(J/Psi→mu+mu-). With no significant signal observed in the high m(antiLambda p) region above 2.8 GeV/c2, an upper limit is set to be B_{high}(B+->antiLambda pmu+mu-)<2.8(3.7)x10-9 at the 90% (95%) confidence level.
Evidence for the Rare Decay B+ -> Lambda- p mu+mu-
Celestino I.Membro del Collaboration Group
;Cordova G.Membro del Collaboration Group
;Kleijne N.Membro del Collaboration Group
;Morello M. J.Membro del Collaboration Group
;Passaro D.Membro del Collaboration Group
;Pica L.Membro del Collaboration Group
;Riccardi D.Membro del Collaboration Group
;Xu A.Membro del Collaboration Group
;
2026
Abstract
A search for the rare decay B+->Lambda-pmu+mu- is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of sqrt(s)=13 TeV, corresponding to an integrated luminosity of 5.4 fb-1. An excess of events is found with respect to the background-only expectation, with a signal significance of 3.5 standard deviations, in the low invariant-mass region of m(antiLambda p)<2.8 GeV/c2. The branching fraction is measured to be B_{low}(B+ ->antiLambda pmu+mu-) =(1.70-0.56+0.65(stat)\pm0.17(syst)\pm0.14(ext))x10-8, where the last uncertainty is due to external inputs on B(B+->J/Psi antiΛ p)xB(J/Psi→mu+mu-). With no significant signal observed in the high m(antiLambda p) region above 2.8 GeV/c2, an upper limit is set to be B_{high}(B+->antiLambda pmu+mu-)<2.8(3.7)x10-9 at the 90% (95%) confidence level.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.



