Resonance X(4630)

Abstract

We investigate the structure $X(4630)$ discovered by the LHCb Collaboration in the process ${B}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\phi}{K}^{+}$ as a resonance in the $J/\ensuremath{\psi}\ensuremath{\phi}$ mass distribution. We explore this resonance as a diquark-antidiquark state $X=[cs][\overline{c}\overline{s}]$ with spin-parities ${J}^{\mathrm{PC}}={1}^{\ensuremath{-}+}$. Its mass and current coupling are calculated using the QCD two-point sum rule method by taking into account vacuum condensates up to dimension 10. We also study decays of this tetraquark to mesons $J/\ensuremath{\psi}\ensuremath{\phi}$, ${\ensuremath{\eta}}_{c}{\ensuremath{\eta}}^{(\ensuremath{'})}$ and ${\ensuremath{\chi}}_{c1}{\ensuremath{\eta}}^{(\ensuremath{'})}$, and compute partial widths of these channels. To this end, we employ the light-cone sum rule approach and technical methods of soft-meson approximation to extract strong coupling at relevant tetraquark-meson-meson vertices. Our predictions for the mass $m=(4632\ifmmode\pm\else\textpm\fi{}60)\text{ }\text{ }\mathrm{MeV}$ and width $\mathrm{\ensuremath{\Gamma}}=(159\ifmmode\pm\else\textpm\fi{}31)\text{ }\text{ }\mathrm{MeV}$ of $X$ are in a very nice agreement with recent measurements of the LHCb Collaboration. These results allow us to interpret the resonance $X(4630)$ as the tetraquark $X$ with spin-parities ${J}^{\mathrm{PC}}={1}^{\ensuremath{-}+}$.