Measurement of the D s + → ℓ + ν ℓ branching fractions and the decay constant f D s +

Le résumé fourni par la source

Using $482\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ collision data collected at a center-of-mass energy of $\sqrt{s}=4.009\text{ }\text{ }\mathrm{GeV}$ with the BESIII detector, we measure the branching fractions of the decays ${D}_{s}^{+}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\nu}}_{\ensuremath{\mu}}$ and ${D}_{s}^{+}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}{\ensuremath{\nu}}_{\ensuremath{\tau}}$. By constraining the ratio of decay rates of ${D}_{s}^{+}$ to ${\ensuremath{\tau}}^{+}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ and to ${\ensuremath{\mu}}^{+}{\ensuremath{\nu}}_{\ensuremath{\mu}}$ to the Standard Model prediction, the branching fractions are determined to be $\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\nu}}_{\ensuremath{\mu}})=(0.495\ifmmode\pm\else\textpm\fi{}0.067\ifmmode\pm\else\textpm\fi{}0.026)%$ and $\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}{\ensuremath{\nu}}_{\ensuremath{\tau}})=\phantom{\rule{0ex}{0ex}}(4.83\ifmmode\pm\else\textpm\fi{}0.65\ifmmode\pm\else\textpm\fi{}0.26)%$. Using these branching fractions, we obtain a value for the decay constant ${f}_{{D}_{s}^{+}}$ of $(241.0\ifmmode\pm\else\textpm\fi{}16.3\ifmmode\pm\else\textpm\fi{}6.5)\text{ }\text{ }\mathrm{MeV}$, where the first error is statistical and the second systematic.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.