Y(3940) as a Mixed Charmonium-Molecule State

Abstract

Using the QCD sum rules approach we study the mass and decay width of the channel $J/\psi +\omega$ for the $Y(3940)$ state. We assume that it can be described by a mixed charmonium-molecule scalar state, $({\chi }_{c0})-(D^{\ast }{D}^{\ast })$ current, with $J^{PC}=0^{++}$ quantum numbers. For the mixing angle $(76.0\pm 5.0{)}^0$, we obtain the value $M=(3.95\pm 0.11)$ GeV for the mass, which is in good agreement with the experimental mass of the $Y(3940)$ state. For the decay width into the channel $Y\to J/\psi +\omega$, we find the value ${\Gamma }_Y=(1.7\pm 0.6)$ MeV, which is also compatible with the experimental data. We thus conclude that the present description of the $Y(3940)$ as a mixed charmonium-molecule state is a possible scenario to explain the structure of this state.

Comments: 8 pages, 5 figures, 1 Table