Study of e+e−→γωJ/ψ and Observation of X(3872)→ωJ/ψ

Le résumé fourni par la source

We study the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\omega}J/\ensuremath{\psi}$ process using $11.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ ${e}^{+}{e}^{\ensuremath{-}}$ annihilation data taken at center-of-mass energies from $\sqrt{s}=4.008\text{ }\text{ }\mathrm{GeV}$ to 4.600 GeV with the BESIII detector at the BEPCII storage ring. The $X(3872)$ resonance is observed for the first time in the $\ensuremath{\omega}J/\ensuremath{\psi}$ system with a significance of more than $5\ensuremath{\sigma}$. The relative decay ratio of $X(3872)\ensuremath{\rightarrow}\ensuremath{\omega}J/\ensuremath{\psi}$ and ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$ is measured to be $\mathcal{R}={1.6}_{\ensuremath{-}0.3}^{+0.4}\ifmmode\pm\else\textpm\fi{}0.2$, where the first uncertainty is statistical and the second systematic (the same hereafter). The $\sqrt{s}$-dependent cross section of ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\gamma}X(3872)$ is also measured and investigated, and it can be described by a single Breit-Wigner resonance, referred to as the $Y(4200)$, with a mass of ${4200.6}_{\ensuremath{-}13.3}^{+7.9}\ifmmode\pm\else\textpm\fi{}3.0\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ and a width of ${115}_{\ensuremath{-}26}^{+38}\ifmmode\pm\else\textpm\fi{}12\text{ }\text{ }\mathrm{MeV}$. In addition, to describe the $\ensuremath{\omega}J/\ensuremath{\psi}$ mass distribution above $3.9\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, we need at least one additional Breit-Wigner resonance, labeled as $X(3915)$, in the fit. The mass and width of the $X(3915)$ are determined. The resonant parameters of the $X(3915)$ agree with those of the $Y(3940)$ in $B\ensuremath{\rightarrow}K\ensuremath{\omega}J/\ensuremath{\psi}$ and of the $X(3915)$ in $\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}\ensuremath{\omega}J/\ensuremath{\psi}$ observed by the Belle and BABAR experiments within errors.

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