Differential branching fraction and angular analysis of Λ {/b 0} → Λμ + μ - decays

The differential branching fraction of the rare decay Λ 0 b → Λµ+µ − is measured as a function of q 2 , 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. Evi...

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Detalles Bibliográficos
Autores: LHCb collaboration, Badalov, Alexey, Casanova Mohr, Raimon, Garrido Beltrán, Lluís, Gascón Fora, David, Graciani Díaz, Ricardo, Graugés Pous, Eugeni, Marin Benito, Carla, Picatoste Olloqui, Eduardo, Rives Molina, Vicente José, Ruiz, Hugo (Ruiz Pérez)
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:2445/185666
Acceso en línea:https://hdl.handle.net/2445/185666
Access Level:acceso abierto
Palabra clave:Hadrons
Gran Col·lisionador d'Hadrons
Física de partícules
Experiments
Large Hadron Collider (France and Switzerland)
Particle physics
Descripción
Sumario:The differential branching fraction of the rare decay Λ 0 b → Λµ+µ − is measured as a function of q 2 , 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 q 2 region below the square of the J/ψ mass. Integrating over 15 < q2 < 20 GeV2/c4 the branching fraction is measured as dB(Λ 0 b → Λµ+µ −)/dq 2 = (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/ψ Λ, respectively. In the q 2 intervals where the signal is observed, angular distributions are studied and the forward-backward asymmetries in the dimuon (A` FB) and hadron (Ah FB) systems are measured for the first time. In the range 15 < q2 < 20 GeV2/c4 they are found to be A ` FB = −0.05 ± 0.09 (stat) ± 0.03 (syst) and A h FB = −0.29 ± 0.07 (stat) ± 0.03 (syst).

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