The differential branching fraction of the rare decay Λ b 0  → 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(GeV2/4)−1, where the uncertainties are statistical, systematic and due to the normalisation mode, Λ b 0  → 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 FB ℓ ) and hadron (A FB h ) systems are measured for the first time. In the range 15 < q2 < 20 GeV2/c4 they are found to be ℓFB=−0.05±0.09(stat)±0.03(syst)andℎFB=−0.29±0.07(stat)±0.03(syst).

Differential branching fraction and angular analysis of Λ(formula presented.)decays / Aaij, R., Adeva, B., Adinolfi, M., Affolder, A., Ajaltouni, Z., Akar, S., Albrecht, J., Alessio, F., Alexander, M., Ali, S., Alkhazov, G., Alvarez Cartelle, P., Alves, A.A., Amato, S., Amerio, S., Amhis, Y., An, L., Anderlini, L., Anderson, J., Andreotti, M., et al.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1126-6708. - 2015:6(2015). [10.1007/JHEP06(2015)115]

Differential branching fraction and angular analysis of Λ(formula presented.)decays

Capriotti, L.;Casse, G.;Sarti, A.;Sciubba, A.;
2015

Abstract

The differential branching fraction of the rare decay Λ b 0  → 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(GeV2/4)−1, where the uncertainties are statistical, systematic and due to the normalisation mode, Λ b 0  → 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 FB ℓ ) and hadron (A FB h ) systems are measured for the first time. In the range 15 < q2 < 20 GeV2/c4 they are found to be ℓFB=−0.05±0.09(stat)±0.03(syst)andℎFB=−0.29±0.07(stat)±0.03(syst).
2015
Rare decay Hadron-Hadron Scattering Branching fraction B physics Flavour Changing Neutral Currents
01 Pubblicazione su rivista::01a Articolo in rivista
Differential branching fraction and angular analysis of Λ(formula presented.)decays / Aaij, R., Adeva, B., Adinolfi, M., Affolder, A., Ajaltouni, Z., Akar, S., Albrecht, J., Alessio, F., Alexander, M., Ali, S., Alkhazov, G., Alvarez Cartelle, P., Alves, A.A., Amato, S., Amerio, S., Amhis, Y., An, L., Anderlini, L., Anderson, J., Andreotti, M., et al.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1126-6708. - 2015:6(2015). [10.1007/JHEP06(2015)115]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1074945
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