Study of the decay Ds+→K+K−e+νe

Le résumé fourni par la source

Using $214\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data recorded by the BABAR detector at the PEPII electron-positron collider, we study the decay ${D}_{s}^{+}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{e}^{+}{\ensuremath{\nu}}_{e}$. Except for a small S-wave contribution, the events with ${K}^{+}{K}^{\ensuremath{-}}$ masses in the range $1.01--1.03\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ correspond to $\ensuremath{\phi}$ mesons. For ${D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\phi}{e}^{+}{\ensuremath{\nu}}_{e}$ decays, we measure the relative normalization of the Lorentz invariant form factors at ${q}^{2}=0$, ${r}_{V}=V(0)/{A}_{1}(0)=1.849\ifmmode\pm\else\textpm\fi{}0.060\ifmmode\pm\else\textpm\fi{}0.095$, ${r}_{2}={A}_{2}(0)/{A}_{1}(0)=0.763\ifmmode\pm\else\textpm\fi{}0.071\ifmmode\pm\else\textpm\fi{}0.065$ and the pole mass of the axial-vector form factors ${m}_{A}=({2.28}_{\ensuremath{-}0.18}^{+0.23}\ifmmode\pm\else\textpm\fi{}0.18)\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. Within the same ${K}^{+}{K}^{\ensuremath{-}}$ mass range, we also measure the relative branching fraction $\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{e}^{+}{\ensuremath{\nu}}_{e})/\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+})=0.558\ifmmode\pm\else\textpm\fi{}0.007\ifmmode\pm\else\textpm\fi{}0.016$, from which we obtain the total branching fraction $\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\phi}{e}^{+}{\ensuremath{\nu}}_{e})=(2.61\ifmmode\pm\else\textpm\fi{}0.03\ifmmode\pm\else\textpm\fi{}0.08\ifmmode\pm\else\textpm\fi{}0.15)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$. By comparing this value with the predicted decay rate, we extract ${A}_{1}(0)=0.607\ifmmode\pm\else\textpm\fi{}0.011\ifmmode\pm\else\textpm\fi{}0.019\ifmmode\pm\else\textpm\fi{}0.018$. The stated uncertainties are statistical, systematic, and from external inputs.

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