First Experimental Study of the Purely Leptonic Decay Ds*+ → e+ve

作者：Ablikim, M.; Achasov, M. N.; Adlarson, P.; 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.; 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, T. T.; Chang, W. L.; Che, G. R.; Chelkov, G.; Chen, C.; Chen, Chao; Chen, G.; Chen, H. S.

来源：Physical Review Letters, 2023, 131(14): 141802.

DOI：10.1103/PhysRevLett.131.141802

• D-ASTERISK
• D-S
• CONSTANTS
• MESONS
• LIGHT
• TOF

Using 7.33 fb(-1) of e(+)e(-) collision data taken with the BESIII detector at the BEPCII collider, we report the first experimental study of the purely leptonic decay D-s*(+) -> e(+)v(e). Our data contain a signal of this decay with a statistical significance of 2.9s. The branching fraction of D-s*(+) -> e(+)v(e) is measured to be (2.1(-0.9stat)(+1.2) +/- 0.2(syst)+ x 10(-5), corresponding to an upper limit of 4.0 x 10(-5) at the 90% confidence level. Taking the total width of the D-s*(+) [(0.070 +/- 0.028+ keV] predicted with the radiative D-s*(+) decay from the lattice QCD calculation as input, the decay constant of the D-s*(+) is determined to be f(Ds*+) = (214-(+61)(46stat) +/- 44(syst)) MeV, corresponding to an upper limit of 354 MeVat the 90% confidence level.