Observation of h1(1380) in the J/ψ→η′KK¯π decay

Le résumé fourni par la source

Using $1.31\ifmmode\times\else\texttimes\fi{}{10}^{9}\text{ }\text{ }J/\ensuremath{\psi}$ events collected by the BESIII detector at the BEPCII ${e}^{+}{e}^{\ensuremath{-}}$ collider, we report the first observation of the ${h}_{1}(1380)$ in $J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{h}_{1}(1380)$ with a significance of more than ten standard deviations. The mass and width of the possible axial-vector strangeonium candidate ${h}_{1}(1380)$ are measured to be $M=(1423.2\ifmmode\pm\else\textpm\fi{}2.1\ifmmode\pm\else\textpm\fi{}7.3)\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ and $\mathrm{\ensuremath{\Gamma}}=(90.3\ifmmode\pm\else\textpm\fi{}9.8\ifmmode\pm\else\textpm\fi{}17.5)\text{ }\text{ }\mathrm{MeV}$. The product branching fractions, assuming no interference, are determined to be $\mathcal{B}(J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{h}_{1}(1380))\ifmmode\times\else\texttimes\fi{}\mathcal{B}({h}_{1}(1380)\ensuremath{\rightarrow}{K}^{*}(892{)}^{+}{K}^{\ensuremath{-}}+\mathrm{c}.\mathrm{c}.)=(1.51\ifmmode\pm\else\textpm\fi{}0.09\ifmmode\pm\else\textpm\fi{}0.21)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ in ${\ensuremath{\eta}}^{\ensuremath{'}}{K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ mode and $\mathcal{B}(J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{h}_{1}(1380))\ifmmode\times\else\texttimes\fi{}\mathcal{B}({h}_{1}(1380)\ensuremath{\rightarrow}{K}^{*}(892)\overline{K}+\mathrm{c}.\mathrm{c}.)=(2.16\ifmmode\pm\else\textpm\fi{}0.12\ifmmode\pm\else\textpm\fi{}0.29)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ in ${\ensuremath{\eta}}^{\ensuremath{'}}{K}_{S}^{0}{K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$ mode. The first uncertainties are statistical and the second are systematic. Isospin symmetry violation is observed in the decays ${h}_{1}(1380)\ensuremath{\rightarrow}{K}^{*}(892{)}^{+}{K}^{\ensuremath{-}}+\mathrm{c}.\mathrm{c}.$ and ${h}_{1}(1380)\ensuremath{\rightarrow}{K}^{*}(892{)}^{0}{\overline{K}}^{0}+\mathrm{c}.\mathrm{c}.$. Based on the measured ${h}_{1}(1380)$ mass, the mixing angle between the states ${h}_{1}(1170)$ and ${h}_{1}(1380)$ is determined to be $(35.9\ifmmode\pm\else\textpm\fi{}2.6)\ifmmode^\circ\else\textdegree\fi{}$, consistent with theoretical expectations.

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