Measurements of the branching fractions of semileptonic $D_s^{+}$ decays via $e^{+}{e}^{-}\to D_s^{\ast +}{D}_s^{\ast -}$

Abstract

We measure the absolute branching fractions of semileptonic $D_s^{+}$ decays via the $e^{+}{e}^{-}\to D_s^{\ast +}{D}_s^{\ast -}$ process using $e^{+}{e}^{-}$ collision data corresponding to an integrated luminosity of $10.64{\mathrm{fb}}^{-1}$ collected by the BESIII detector at center-of-mass energies between 4.237 and 4.699 GeV. The branching fractions are $\mathcal{B}(D_s^{+}\to \hat{I}\cdot e^{+}\hat{I}{½}_e)=(2.35\pm 0.11_{\mathrm{stat}}\pm 0.10_{\mathrm{syst}})\%,$ $\mathcal{B}(D_s^{+}\to \hat{I}{\cdot }^{\prime }{e}^{+}\hat{I}{½}_e)=(0.82\pm 0.09_{\mathrm{stat}}\pm 0.04_{\mathrm{syst}})\%,$ $\mathcal{B}(D_s^{+}\to \ddot{I}•e^{+}\hat{I}{½}_e)=(2.21\pm 0.16_{\mathrm{stat}}\pm 0.11_{\mathrm{syst}})\%,$ $\mathcal{B}(D_s^{+}\to f_0(980)e^{+}\hat{I}{½}_e,f_0(980)\to \ddot{I}{€}^{+}\ddot{I}{€}^{-})=(0.15\pm 0.02_{\mathrm{stat}}\pm 0.01_{\mathrm{syst}})\%,$ $\mathcal{B}(D_s^{+}\to K^0{e}^{+}\hat{I}{½}_e)=(0.24\pm 0.04_{\mathrm{stat}}\pm 0.01_{\mathrm{syst}})\%,$ and $\mathcal{B}(D_s^{+}\to K^{\ast 0}{e}^{+}\hat{I}{½}_e)=(0.19\pm 0.03_{\mathrm{stat}}\pm 0.01_{\mathrm{syst}})\%.$ These results are consistent with those measured via the $e^{+}{e}^{-}\to D_s^{\ast \pm }{D}_s^{\mp }$ process by BESIII and CLEO. The hadronic transition form factors $D_s^{+}\to \hat{I}\cdot e^{+}\hat{I}{½}_e$, $D_s^{+}\to \hat{I}{\cdot }^{\prime }{e}^{+}\hat{I}{½}_e$, and $D_s^{+}\to K^0{e}^{+}\hat{I}{½}_e$ at four-momentum transfer squared $q^2$ = 0 are determined to be $f^{\hat{I}}{\cdot }_{+}(0)=0.482\pm 0.011_{\mathrm{stat}}\pm 0.009_{\mathrm{syst}}\pm 0.004_{\mathrm{input}},$ $f_{+}^{\hat{I}{\cdot }^{\prime }}(0)=0.562\pm 0.031_{\mathrm{stat}}\pm 0.014_{\mathrm{syst}}\pm 0.003_{\mathrm{input}},$ and $f_{+}^{K^0}(0)=0.624\pm 0.052_{\mathrm{stat}}\pm 0.013_{\mathrm{syst}}\pm 0.002_{\mathrm{input}}.$

18 pages, 5 figures