Observation of B+→D¯*0τ+ντ and evidence for B+→D¯0τ+ντ at Belle

Le résumé fourni par la source

We present measurements of ${B}^{+}\ensuremath{\rightarrow}{\overline{D}}^{*0}{\ensuremath{\tau}}^{+}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ and ${B}^{+}\ensuremath{\rightarrow}{\overline{D}}^{0}{\ensuremath{\tau}}^{+}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ decays in a data sample of $657\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. We find ${446}_{\ensuremath{-}56}^{+58}$ ${B}^{+}\ensuremath{\rightarrow}{\overline{D}}^{*0}{\ensuremath{\tau}}^{+}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ events with a significance of 8.1 standard deviations, and ${146}_{\ensuremath{-}41}^{+42}$ ${B}^{+}\ensuremath{\rightarrow}{\overline{D}}^{0}{\ensuremath{\tau}}^{+}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ events with a significance of 3.5 standard deviations. The latter signal provides the first evidence for this decay mode. The measured branching fractions are $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\overline{D}}^{*0}{\ensuremath{\tau}}^{+}{\ensuremath{\nu}}_{\ensuremath{\tau}})=({2.12}_{\ensuremath{-}0.27}^{+0.28}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.29(\mathrm{syst}))%$ and $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\overline{D}}^{0}{\ensuremath{\tau}}^{+}{\ensuremath{\nu}}_{\ensuremath{\tau}})=(0.77\ifmmode\pm\else\textpm\fi{}0.22(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.12(\mathrm{syst}))%$.

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