- Accepted Paper
First measurement of the decay, study of dynamics and test of lepton universality with decays
Phys. Rev. Lett. - Accepted 4 November, 2026
DOI: https://doi.org/10.1103/flqh-zxzr
Phys. Rev. Lett. - Accepted 4 November, 2026
DOI: https://doi.org/10.1103/flqh-zxzr
We report the first measurement of the semileptonic decay and an improved measurement of the decay using a sample of of annihilation data collected at center-of-mass energies between 4.128 to 4.226~GeV with the BESIII detector at the BEPCII collider. We measure the branching fractions to be $\mathcal B({D^+_s\rightarrow K^*(892)^0 \mu^+\nu_{\mu}})=(2.07\pm0.22_{\rm stat}\pm0.10_{\rm syst})\times10^{-3}$ and $\mathcal B({D^+_s\rightarrow K^*(892)^0 e^+\nu_{e}})=(2.14\pm0.18_{\rm stat}\pm0.10_{\rm syst})\times10^{-3}$. Based on a simultaneous study of the dynamics in two semileptonic decays, the hadronic form factor parameters in the transition are determined to be $r_{V} = V(0)/A_1(0) = 1.63 \pm 0.14_{\rm stat} \pm 0.08_{\rm syst}$, $r_{2} = A_2(0)/A_1(0) = 0.60 \pm 0.13_{\rm stat} \pm 0.06_{\rm syst}$, and $A_1(0)=0.56 \pm 0.02_{\rm stat} \pm 0.01_{\rm syst}$, where is the vector form factor and are the axial-vector form factors evaluated at . The precision of and is improved by twofold and is measured for the first time. We also report the first model-independent measurements of the differential decay rates and the lepton forward-backward asymmetries for decays. Based on these measurements, we perform a test of lepton flavor universality in full and separate intervals with decays. No violation is found within uncertainties. Our results present for the first time a complete study of the dynamics in the transition, and provide stringent tests of various non-perturbative theoretical calculations.
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