Observation of a State X(2600) in the π+π−η′ System in the Process J/ψ→γπ+π−η′

Le résumé fourni par la source

Based on $(10087\ifmmode\pm\else\textpm\fi{}44)\ifmmode\times\else\texttimes\fi{}{10}^{6}\text{ }\text{ }J/\ensuremath{\psi}$ events collected with the BESIII detector, the process $J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\eta}}^{\ensuremath{'}}$ is studied using two largest decay channels of the ${\ensuremath{\eta}}^{\ensuremath{'}}$ meson, ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$, $\ensuremath{\eta}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$. A new resonance, which we denote as the $X(2600)$, is observed with a statistical significance larger than $20\ensuremath{\sigma}$ in the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\eta}}^{\ensuremath{'}}$ invariant mass spectrum, and it has a connection to a structure around ${1.5\text{ }\text{ }\mathrm{GeV}/c}^{2}$ in the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ invariant mass spectrum. A simultaneous fit on the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\eta}}^{\ensuremath{'}}$ and ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ invariant mass spectra with the two ${\ensuremath{\eta}}^{\ensuremath{'}}$ decay modes indicates that the mass and width of the $X(2600)$ state are $2618.3\ifmmode\pm\else\textpm\fi{}2.{0}_{\ensuremath{-}1.4}^{+16.3}\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ and $195\ifmmode\pm\else\textpm\fi{}{5}_{\ensuremath{-}17}^{+26}\text{ }\text{ }\mathrm{MeV}$, 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.