First Experimental Study of the Purely Leptonic Decay D_{s}^{*+}→e^{+}ν_{e}

Area of Science:

• Particle Physics
• Experimental Particle Physics
• Quantum Chromodynamics

Background:

• The D_{s}^{*+} meson is a crucial probe for understanding fundamental particle interactions.
• Precise measurements of its properties, like leptonic decays, test theoretical models.

Purpose of the Study:

• To report the first experimental investigation of the purely leptonic decay D_{s}^{*+}→e^{+}ν_{e}.
• To measure the branching fraction and determine the decay constant of the D_{s}^{*+} meson.

Main Methods:

• Analysis of 7.33 fb^{-1} of e^{+}e^{-} collision data collected by the BESIII detector at the BEPCII collider.
• Statistical analysis to identify the signal for the D_{s}^{*+}→e^{+}ν_{e} decay.
• Incorporation of lattice QCD calculations for the total width of D_{s}^{*+} to determine the decay constant.

Main Results:

• A signal for the D_{s}^{*+}→e^{+}ν_{e} decay was observed with a statistical significance of 2.9σ.
• The branching fraction was measured as (2.1_{-0.9}^{+1.2}±0.2)×10^{-5}, with an upper limit of 4.0×10^{-5} at 90% confidence level.
• The decay constant f_{D_{s}^{*+}} was determined to be (214_{-46}^{+61}±44) MeV, with an upper limit of 354 MeV at 90% confidence level.

Conclusions:

• This study provides the first experimental constraints on the purely leptonic decay of the D_{s}^{*+} meson.
• The results offer valuable data for refining theoretical predictions in particle physics and quantum chromodynamics.