Measurement of the branching fraction of $D^{+}\to {\tau }^{+}{\nu }_{\tau }$

Abstract

By analyzing $e^{+}{e}^{-}$ collision data with an integrated luminosity of 7.9~fb${}^{-1}$ collected with the BESIII detector at the center-of-mass energy of 3.773~GeV, the branching fraction of $D^{+}\to {\tau }^{+}{\nu }_{\tau }$ is determined as $\mathcal{B}=(9.9\pm 1.1_{\mathrm{stat}}\pm 0.5_{\mathrm{syst}})\times 10^{-4}$. Taking the most precise result $\mathcal{B}(D^{+}\to {\mu }^{+}{\nu }_{\mu })=(3.981\pm 0.079_{\mathrm{stat}}\pm 0.040_{\mathrm{syst}})\times 10^{-4}$, we determine $R_{\tau /\mu }=\Gamma (D^{+}\to {\tau }^{+}{\nu }_{\tau })/\Gamma (D^{+}\to {\mu }^{+}{\nu }_{\mu })=2.49\pm 0.31$, achieving a factor of two improvement in precision compared to the previous BESIII result. This measurement is in agreement with the standard model prediction of lepton flavor universality within one standard deviation.

References in corpus (3)

• FLAG Review 2021
• Recent Progress in Leptonic and Semileptonic Decays of Charmed Hadrons
• Discerning new physics in charm meson leptonic and semileptonic decays