2026-04-17T12:11:10Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1856662025-11-21T05:47:37Zcom_2072_1057col_2072_478823col_2072_478917

00925njm 22002777a 4500 dc LHCb collaboration author Badalov, Alexey author Casanova Mohr, Raimon author Garrido Beltrán, Lluís author Gascón Fora, David author Graciani Díaz, Ricardo author Graugés Pous, Eugeni author Marin Benito, Carla author Picatoste Olloqui, Eduardo author Rives Molina, Vicente José author Ruiz, Hugo (Ruiz Pérez) author 2022-05-17T15:58:40Z 2022-05-17T15:58:40Z 2015-06-17 2022-05-17T15:58:40Z 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). Hadrons Gran Col·lisionador d'Hadrons Física de partícules Experiments Hadrons Large Hadron Collider (France and Switzerland) Particle physics Experiments Differential branching fraction and angular analysis of Λ {/b 0} → Λμ + μ - decays