Measurement of the branching fraction of leptonic decay $D_s^{+}\to {\tau }^{+}{\nu }_{\tau }$ via ${\tau }^{+}\to {\pi }^{+}{\pi }^0{\bar{\nu }}_{\tau }$

Abstract

By analyzing $6.32{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data collected at the center-of-mass energies between 4.178 and 4.226\,GeV with the BESIII detector, we determine the branching fraction of the leptonic decay $D_s^{+}\to {\tau }^{+}{\nu }_{\tau }$ with ${\tau }^{+}\to {\pi }^{+}{\pi }^0{\bar{\nu }}_{\tau }$, to be ${\mathcal{B}}_{D_s^{+}\to {\tau }^{+}{\nu }_{\tau }}=(5.29\pm 0.25_{\mathrm{stat}}\pm 0.20_{\mathrm{syst}})\%$. We estimate the product of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cs}|$ and the $D_s^{+}$ decay constant $f_{D_s^{+}}$ to be $f_{D_s^{+}}|V_{cs}|=(244.8\pm 5.8_{\mathrm{stat}}\pm 4.8_{\mathrm{syst}})\mathrm{MeV}$ using the known values of the ${\tau }^{+}$ and $D_s^{+}$ masses as well as the $D_s^{+}$ lifetime, together with our branching fraction measurement. Combining with the value of $|V_{cs}|$ obtained from a global fit in the standard model and $f_{D_s^{+}}$ from lattice quantum chromodynamics, we obtain $f_{D_s^{+}}=(251.6\pm 5.9_{\mathrm{stat}}\pm 4.9_{\mathrm{syst}})$\,MeV and $|V_{cs}|=0.980\pm 0.023_{\mathrm{stat}}\pm 0.019_{\mathrm{syst}}$.

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• Decay Constants of Pseudoscalar $D$-mesons in Lattice QCD with Domain-Wall Fermion
• Measurement of the Dynamics of the Decays $D_s^{+}\to {\eta }^{(\prime )}{e}^{+}{\nu }_e$
• Measurement of the $D_s^{+}\to {\ell }^{+}{\nu }_{\ell }$ branching fractions and the decay constant $f_{D_s^{+}}$
• Search for the decay $D_s^{+}\to \gamma e^{+}{\nu }_e$

Cited by in corpus (10)

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• Measurements of the branching fractions of semileptonic $D_s^{+}$ decays via $e^{+}{e}^{-}\to D_s^{\ast +}{D}_s^{\ast -}$
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• Search for baryon and lepton number violating decays of ${\Xi }^0$ hyperons
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