Y(3940) as a mixed charmonium-molecule state
Data de publicação2014-04-10
Direito de acesso
MetadadosExibir registro completo
Using the QCD sum rules approach, we study the mass and the decay widths of the Y(3940) state, assuming that it can be described by a mixed charmonium-molecule scalar state, i.e., a mixture between chi(c0) charmonium and D*(D) over bar* molecule. Using a current with J(PC) = 0(++), we estimate for the mixing angle, theta = (76.0+/-5.0)degrees, resulting in a mass value of M-Y = (3.95 +/- 0.11) GeV, which is in reasonable agreement with the experimental mass of the Y(3940) state. For the decay width, we evaluate the channels Y -> J/psi omega and Y -> gamma gamma. We find the values Gamma(Y -> J/psi omega) approximate to (1.7 +/- 0.6) MeV and Gamma(Y ->gamma gamma) approximate to (1.6 +/- 1.3) KeV, respectively. We also study the decay process of this state into channels containing D (D) over bar mesons in the final state. The result for the order of magnitude of the product Gamma(Y ->gamma gamma) X Gamma(Y -> J/psi omega) similar to O (10(3)) KeV(2) is also in reasonable agreement 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 such a state.