Observation of ψ(3686)→pp¯η′ and improved measurement of J/ψ→pp¯η′

Résumé fourni par la source

We observe the process $\ensuremath{\psi}(3686)\ensuremath{\rightarrow}p\overline{p}{\ensuremath{\eta}}^{\ensuremath{'}}$ for the first time, with a statistical significance higher than $10\ensuremath{\sigma}$, and measure the branching fraction of $J/\ensuremath{\psi}\ensuremath{\rightarrow}p\overline{p}{\ensuremath{\eta}}^{\ensuremath{'}}$ with an improved accuracy compared to earlier studies. The measurements are based on $4.48\ifmmode\times\else\texttimes\fi{}{10}^{8}\text{ }\text{ }\ensuremath{\psi}(3686)$ and $1.31\ifmmode\times\else\texttimes\fi{}{10}^{9}\text{ }\text{ }J/\ensuremath{\psi}$ events collected by the BESIII detector operating at the BEPCII. The branching fractions are determined to be $\mathcal{B}(\ensuremath{\psi}(3686)\ensuremath{\rightarrow}p\overline{p}{\ensuremath{\eta}}^{\ensuremath{'}})=(1.10\ifmmode\pm\else\textpm\fi{}0.10\ifmmode\pm\else\textpm\fi{}0.08)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ and $\mathcal{B}(J/\ensuremath{\psi}\ensuremath{\rightarrow}p\overline{p}{\ensuremath{\eta}}^{\ensuremath{'}})=(1.26\ifmmode\pm\else\textpm\fi{}0.02\ifmmode\pm\else\textpm\fi{}0.07)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, where the first uncertainties are statistical and the second ones systematic. Additionally, the $\ensuremath{\eta}\ensuremath{-}{\ensuremath{\eta}}^{\ensuremath{'}}$ mixing angle is determined to be $\ensuremath{-}24\ifmmode^\circ\else\textdegree\fi{}\ifmmode\pm\else\textpm\fi{}11\ifmmode^\circ\else\textdegree\fi{}$ based on $\ensuremath{\psi}(3686)\ensuremath{\rightarrow}p\overline{p}{\ensuremath{\eta}}^{\ensuremath{'}}$, and $\ensuremath{-}24\ifmmode^\circ\else\textdegree\fi{}\ifmmode\pm\else\textpm\fi{}9\ifmmode^\circ\else\textdegree\fi{}$ based on $J/\ensuremath{\psi}\ensuremath{\rightarrow}p\overline{p}{\ensuremath{\eta}}^{\ensuremath{'}}$, respectively.

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