Resonance X(3960) as a hidden charm-strange scalar tetraquark

Abstract

We investigate features of the hidden charm-strange scalar tetraquark cc over bar ss over bar by calculating its spectral parameters and width, and we compare the obtained results with the mass and width of the resonance X(3960) discovered recently in the LHCb experiment. We model the tetraquark as a diquark-antidiquark state X = [cs][c over bar s over bar ] with spin-parities JPC = 0++. The mass and current coupling of X are calculated using the QCD two-point sum rules by taking into account various vacuum condensates up to dimension 10. The width of the tetraquark X is estimated via the decay channels X -> D+s D-s and X -> eta c eta(0). The partial widths of these processes are expressed in terms of couplings G, g1, and g2, which describe the strong interactions of particles at the vertices XD+s D-s , X eta c eta 0, and X eta c eta, respectively. Numerical values of G, g1, and g2 are evaluated by employing the three-point sum rule method. Comparing the results m = (3976 +/- 85) MeV and Gamma X = (42.2 +/- 12.0) MeV obtained for parameters of the tetraquark X and experimental data of the LHCb Collaboration, we conclude that the resonance X(3960) can be considered as a candidate to a scalar diquark-antidiquark state.