No abstract

The widths of the strong decays Z + c (3900) → J/ψπ + and Z + c (3900) → ηcρ + are calculated. To this end, the mass and decay constant of the exotic Z + c (3900) state are computed by means of a two-point sum rule. The obtained results are then used to calculate the strong couplings g ZcJ/ψπ and gZ cηc ρ employing QCD sum rules on the light-cone supplied by a technique of the softmeson approximation. We compare our predictions on the mass and decay widths with available experimental data and other theoretical results.

The mass, decay constant and width of a hypothetical charmed partner Xc of the newly observed exotic X b (5568) state are calculated using a technique of QCD sum rule method. The Xc = [su][cd] state with J P = 0 + is described employing two types of the diquark-antidiquark interpolating currents. The evaluation of the mass mX c and decay constant fX c is carried out utilizing the twopoint sum rule method by including vacuum condensates up to eight dimensions. The widths of the decay channels Xc → D − s π + and Xc → D 0 K 0 are also found. To this end, the strong couplings gX cDs π and gX cDK are computed by means of QCD sum rules on the light-cone and soft-meson approximation.