Observation of the Decay X(3872)→π0χc1(1P)

Le résumé fourni par la source

Using a total of $9.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ collision data with center-of-mass energies between 4.15 and 4.30 GeV collected by the BESIII detector, we search for the processes ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\gamma}X(3872)$ with $X(3872)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\chi}}_{cJ}$ for $J=0$, 1, 2. We report the first observation of $X(3872)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\chi}}_{c1}$, a new decay mode of the $X(3872)$, with a statistical significance of more than $5\ensuremath{\sigma}$ for all systematic fit variations. Normalizing to the previously established process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\gamma}X(3872)$ with $X(3872)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$, we find $\mathcal{B}\mathbf{(}X(3872)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\chi}}_{c1}\mathbf{)}/\phantom{\rule{0ex}{0ex}}\mathcal{B}\mathbf{(}X(3872)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}\mathbf{)}=0.8{8}_{\ensuremath{-}0.27}^{+0.33}\ifmmode\pm\else\textpm\fi{}0.10$, where the first error is statistical and the second is systematic. We set 90% confidence level upper limits on the corresponding ratios for the decays to ${\ensuremath{\pi}}^{0}{\ensuremath{\chi}}_{c0}$ and ${\ensuremath{\pi}}^{0}{\ensuremath{\chi}}_{c2}$ of 19 and 1.1, respectively.

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