Precision Measurement of the Branching Fractions of η ′ Decays

Le résumé fourni par la source

Based on a sample of $(1310.6\ifmmode\pm\else\textpm\fi{}7.0)\ifmmode\times\else\texttimes\fi{}{10}^{6}J/\ensuremath{\psi}$ events collected with the BESIII detector, we present measurements of $J/\ensuremath{\psi}$ and ${\ensuremath{\eta}}^{\ensuremath{'}}$ absolute branching fractions using the process $J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\eta}}^{\ensuremath{'}}$. By analyzing events where the radiative photon converts into an ${e}^{+}{e}^{\ensuremath{-}}$ pair, the branching fraction for $J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\eta}}^{\ensuremath{'}}$ is measured to be $(5.27\ifmmode\pm\else\textpm\fi{}0.03\ifmmode\pm\else\textpm\fi{}0.05)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. The absolute branching fractions of the five dominant decay channels of the ${\ensuremath{\eta}}^{\ensuremath{'}}$ are then measured for the first time and are determined to be $\mathcal{B}({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=(29.90\ifmmode\pm\else\textpm\fi{}0.03\ifmmode\pm\else\textpm\fi{}0.55)%$, $\mathcal{B}({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=(41.24\ifmmode\pm\else\textpm\fi{}0.08\ifmmode\pm\else\textpm\fi{}1.24)%$, $\mathcal{B}({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})=(21.36\ifmmode\pm\else\textpm\fi{}0.10\ifmmode\pm\else\textpm\fi{}0.92)%$, $\mathcal{B}({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\omega})=\phantom{\rule{0ex}{0ex}}(2.489\ifmmode\pm\else\textpm\fi{}0.018\ifmmode\pm\else\textpm\fi{}0.074)%$, and $\mathcal{B}({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma})=(2.331\ifmmode\pm\else\textpm\fi{}0.012\ifmmode\pm\else\textpm\fi{}0.035)%$, where the first uncertainties are statistical and the second systematic.

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