Study of the Semileptonic Decay Λ+c → Λe+νe

Ablikim, M.; Achasov, M. N.; Adlarson, P.; Albrecht, M.; Aliberti, R.; Amoroso, A.; An, M. R.; An, Q.; Bai, X. H.; Bai, Y.; Bakina, O.; Ferroli, R. Baldini; Balossino, I; Ban, Y.; Batozskaya, V; Becker, D.; Begzsuren, K.; Berger, N.; Bertani, M.; Bettoni, D.; Bianchi, F.; Bloms, J.; Bortone, A.; Boyko, I; Briere, R. A.; Brueggemann, A.; Cai, H.; Cai, X.; Calcaterra, A.; Cao, G. F.; Cao, N.; Cetin, S. A.; Chang, J. F.; Chang, W. L.; Chelkov, G.; Chen, C.; Chen, Chao; Chen, G.; Chen, H. S.

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摘要

The study of the Cabibbo-favored semileptonic decay Lambda(+)(c) -> Lambda e(+)nu(e) is reported using a 4.5 fb(-1) data sample of e(+)e(-) annihilations collected at center-of-mass energies ranging from 4.600 GeV to 4.699 GeV with the BESIII detector at the BEPCII collider. The branching fraction of the decay is measured to be B(Lambda(+)(c) -> Lambda e(+)nu(e)) = (3.56 +/- 0.11(stat) +/- 0.07(syst))%, which is the most precise measurement to date. Furthermore, we perform an investigation of the internal dynamics in Lambda(+)(c) -> Lambda e(+)nu(e). We provide the first direct comparisons of the differential decay rate and form factors with those predicted from lattice quantum chromodynamics (LQCD) calculations. Combining the measured branching fraction with a q(2)-integrated rate predicted by LQCD, we determine vertical bar V-cs vertical bar = 0.936 +/- 0.017(B) +/- 0.024(LQCD) +/- 0.007(tau Lambda c).

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