Study of Open-Charm Decays and Radiative Transitions of the <i>X</i>(3872)

Abstract

The processes $X(3872)\ensuremath{\rightarrow}{D}^{*0}{\overline{D}}^{0}+\mathrm{c}.\mathrm{c}.,\ensuremath{\gamma}J/\ensuremath{\psi},\ensuremath{\gamma}\ensuremath{\psi}(2S)$, and $\ensuremath{\gamma}{D}^{+}{D}^{\ensuremath{-}}$ are searched for in a $9.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample collected at center-of-mass energies between 4.178 and 4.278 GeV with the BESIII detector. We observe $X(3872)\ensuremath{\rightarrow}{D}^{*0}\overline{{D}^{0}}+\mathrm{c}.\mathrm{c}.$ and find evidence for $X(3872)\ensuremath{\rightarrow}\ensuremath{\gamma}J/\ensuremath{\psi}$ with statistical significances of $7.4\ensuremath{\sigma}$ and $3.5\ensuremath{\sigma}$, respectively. No evident signals for $X(3872)\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\psi}(2S)$ and $\ensuremath{\gamma}{D}^{+}{D}^{\ensuremath{-}}$ are found, and the upper limit on the relative branching ratio ${R}_{\ensuremath{\gamma}\ensuremath{\psi}}\ensuremath{\equiv}{\mathcal{B}[X(3872)\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\psi}(2S)]}/{\mathcal{B}[X(3872)\ensuremath{\rightarrow}\ensuremath{\gamma}J/\ensuremath{\psi}]}&lt;0.59$ is set at 90% confidence level. Measurements of branching ratios relative to decay $X(3872)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$ are also reported for decays $X(3872)\ensuremath{\rightarrow}{D}^{*0}\overline{{D}^{0}}+\mathrm{c}.\mathrm{c}.,\ensuremath{\gamma}\ensuremath{\psi}(2S),\ensuremath{\gamma}J/\ensuremath{\psi}$, and $\ensuremath{\gamma}{D}^{+}{D}^{\ensuremath{-}}$, as well as the non-${D}^{*0}\overline{{D}^{0}}$ three-body decays ${\ensuremath{\pi}}^{0}{D}^{0}\overline{{D}^{0}}$ and $\ensuremath{\gamma}{D}^{0}\overline{{D}^{0}}$.