Search for CP and P violating pseudoscalar decays into ππ

Le résumé fourni par la source

Using a sample of $(225.2\ifmmode\pm\else\textpm\fi{}2.8)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $J/\ensuremath{\psi}$ events collected with the Beijing Spectrometer at the Beijing Electron-Positron Collider, $CP$ and $P$ violating decays of $\ensuremath{\eta}$, ${\ensuremath{\eta}}^{\ensuremath{'}}$, and ${\ensuremath{\eta}}_{c}$ into ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and ${\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$ are searched for in $J/\ensuremath{\psi}$ radiative decays. No significant $\ensuremath{\eta}$, ${\ensuremath{\eta}}^{\ensuremath{'}}$, or ${\ensuremath{\eta}}_{c}$ signal is observed, and $90%$ confidence level upper limits of $\mathcal{B}(\ensuremath{\eta}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})<3.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, $\mathcal{B}({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})<5.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, $\mathcal{B}({\ensuremath{\eta}}_{c}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})<1.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, $\mathcal{B}(\ensuremath{\eta}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})<6.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, $\mathcal{B}({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})<4.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, and $\mathcal{B}({\ensuremath{\eta}}_{c}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})<4.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ are obtained.

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