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.
2026
Settore FIS/01 - Fisica Sperimentale
Settore PHYS-01/A - Fisica sperimentale delle interazioni fondamentali e applicazioni
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/175763
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