Differential branching fraction and angular analysis of Λ 0 b  → Λμ+μ− decays

The differential branching fraction of the rare decay Λ 0 b  → Λμ+μ− is measured as a function of q2, the square of the dimuon invariant mass. The analysis is performed using proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb−1, collected by the LHCb experiment. Eviden...

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Detalles Bibliográficos
Autores: Badalov, Alexey, Calvo Gomez, Miriam, Vilasis-Cardona, Xavier, LHCb Collaboration - CERN
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2015
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:20.500.14342/3137
Acceso en línea:http://hdl.handle.net/20.500.14342/3137
https://doi.org/10.1007/JHEP06(2015)115
Access Level:acceso abierto
Palabra clave:Gran col·lisionador d'hadrons (França i Suïssa)
Partícules (Física nuclear)
Col·lisions (Física nuclear)
Protons
539
Descripción
Sumario:The differential branching fraction of the rare decay Λ 0 b  → Λμ+μ− is measured as a function of q2, the square of the dimuon invariant mass. The analysis is performed using proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb−1, collected by the LHCb experiment. Evidence of signal is observed in the q2 region below the square of the J/ψ mass. Integrating over 15 < q2 < 20 GeV2/c4 the differential branching fraction is measured as dB(Λ0b→Λμ+μ−)/dq2=(1.18+0.09−0.08±0.03±0.27)×10−7(GeV2/c4)−1, where the uncertainties are statistical, systematic and due to the normalisation mode, Λ 0 b  → J/ψΛ, respectively. In the q2 intervals where the signal is observed, angular distributions are studied and the forward-backward asymmetries in the dimuon (A ℓFB ) and hadron (A hFB ) systems are measured for the first time. In the range 15 < q2 < 20 GeV2/c4 they are found to be AℓFB=−0.05±0.09(stat)±0.03(syst)andAhFB=−0.29±0.07(stat)±0.03(syst).