Differential branching fraction and angular analysis of $Λ^0_b \rightarrow Λ μ^+μ^-$ decaysстатья
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Дата последнего поиска статьи во внешних источниках: 18 марта 2016 г.
Аннотация:The differential branching fraction of the rare decay Λ0b→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 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, Λ0b→J/ψΛ , respectively. In the q2 intervals where the signal is observed, angular distributions are studied and the forward-backward asymmetries in the dimuon (AℓFB) and hadron (AhFB) systems are measured for the first time. In the range 15<q2<20 GeV2/c4 they are found to be
AℓFBAhFB=−0.05±0.09(stat)±0.03(syst)\;and=−0.29±0.07(stat)±0.03(syst).