Understanding Y(4274) and X(4320) in the $J/\psi \phi$ invariant mass spectrum

Abstract

In this work we study the structures near 4.3 GeV in the $J/\psi \phi$ invariant mass spectra in B meson decay process $B^+\to J/\psi \phi K^+$ and two photon fusion process $\gamma\gamma\to J/\psi \phi$. The Y(4274) as a $D_sD_{s0}$ $(2317)$ molecular is studied in the Bethe-Salpeter equation approach with quasipotential approximation. The absence of Y(4274) in $\gamma\gamma\to J/\psi \phi$ channel can be well explained by the decay widths of Y(4274) decaying to $\gamma\gamma$ and $J/\psi\phi$. The distribution of mass difference released by CMS collaboration is reproduced by two resonances near 4.3 GeV, Y(4274) and X(4320). The different production mechanism suggests X(4320) observed in the B decay should be the missing $3^3P_1$ charmonium state $\chi''_{c1}$ and different from X(4350) observed in two photon fusion which can be assigned as $\chi''_{c2}$.