Branching fraction measurements of χc0 and χc2 to π0π0 and ηη

Le résumé fourni par la source

Using a sample of $1.06\ifmmode\times\else\texttimes\fi{}{10}^{8}$ ${\ensuremath{\psi}}^{\ensuremath{'}}$ decays collected by the BESIII detector, ${\ensuremath{\chi}}_{c0}$ and ${\ensuremath{\chi}}_{c2}$ decays into ${\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$ and $\ensuremath{\eta}\ensuremath{\eta}$ are studied. The branching fraction results are $\mathrm{Br}({\ensuremath{\chi}}_{c0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})=(3.23\ifmmode\pm\else\textpm\fi{}0.03\ifmmode\pm\else\textpm\fi{}0.23\ifmmode\pm\else\textpm\fi{}0.14)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, $\mathrm{Br}({\ensuremath{\chi}}_{c2}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})=(8.8\ifmmode\pm\else\textpm\fi{}0.2\ifmmode\pm\else\textpm\fi{}0.6\ifmmode\pm\else\textpm\fi{}0.4)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, $\mathrm{Br}({\ensuremath{\chi}}_{c0}\ensuremath{\rightarrow}\ensuremath{\eta}\ensuremath{\eta})=(3.44\ifmmode\pm\else\textpm\fi{}0.10\ifmmode\pm\else\textpm\fi{}0.24\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, and $\mathrm{Br}({\ensuremath{\chi}}_{c2}\ensuremath{\rightarrow}\ensuremath{\eta}\ensuremath{\eta})=(6.5\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, where the uncertainties are statistical, systematic due to this measurement, and systematic due to the branching fractions of ${\ensuremath{\psi}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\chi}}_{cJ}$. The results provide information on the decay mechanism of ${\ensuremath{\chi}}_{c}$ states into pseudoscalars.

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