Measurement of the branching fraction of DDs+ → τ+ντ via τ+ → μ+νμντ

作者：Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; An, M. R.; An, Q.; Bai, Y.; Bakina, O.; Balossino, I.; Ban, Y.; Batozskaya, V.; Begzsuren, K.; Berger, N.; Berlowski, M.; Bertani, M.; Bettoni, D.; Bianchi, F.; Bianco, E.; 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, T. T.; Chang, W. L.; Che, G. R.; Chelkov, G.; Chen, C.; Chen, Chao; Chen, G.; Chen, H. S.

来源：JOURNAL OF HIGH ENERGY PHYSICS, 2023, (9): 124.

DOI：10.1007/JHEP09(2023)124

• e(+)-e(-) Experiments

Utilizing 7.33 fb(-1) of e(+)e(-) collision data taken at the center-of-mass energies of 4.128, 4.157, 4.178, 4.189, 4.199, 4.209, 4.219, and 4.226 GeV with the BESIII detector, the branching fraction of the leptonic decay D+s+ -> tau(+)nu(tau) via tau(+) -> mu(+)nu(mu )is measured to be BD+s ->tau+nu tau = (5.37 +/- 0.17(stat) +/- 0.15(syst))%. Combining this branching fraction with the world averages of the measurements of the masses of tau(+) and D-s(+) as well as the lifetime of D-s(+) , we extract the product of the decay constant of D-s(+) and the c -> s Cabibbo-Kobayashi-Maskawa matrix element to be D- f(s)+ |V-cs| = (246.7 +/- 3.9(stat) +/- 3.6(syst)) MeV. Taking |V-cs| from a global fit in the standard model we obtain fD+s = (253.4 +/- 4.0(stat) +/- 3.7(syst)) MeV. Conversely, taking( f)D(s)(+) from lattice quantum chromodynamics calculations, we obtain |V-cs| = 0.987 +/- 0.016(stat) +/- 0.014(syst).