First Experimental Study of the Purely Leptonic Decay D_s^*+→ e⁺ν_e

2023/04/24 by BESIII Collaboration, Ablikim, M., Achasov, M. N. +615
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)

paper · doi:10.48550/arxiv.2304.12159

Abstract

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⁺ν_e. A signal for the decay D_s^*+→ e⁺ν_e is observed with a statistical significance of 2.9σ. The branching fraction of D_s^*+→ e⁺ν_e is measured to be (2.1^+1.2_{-0.9\rm stat.}±0.2_{\rm syst.})× 10^-5, corresponding to an upper limit of 4.0×10^-5 at the 90% confidence level. Taking the total width of the D_s^*+~((0.070±0.028) keV) predicted by lattice quantum chromodynamics as input, the decay constant of the D^*+_s is determined to be f_Ds^*+=(213.6^+61.0_{-45.8\rm stat.}±43.9_{\rm syst.}) MeV, corresponding to an upper limit of 353.8 MeV at the 90% confidence level.

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