Mechanisms for XcJ → ΦΦ decays

Exclusive decays of Xc J (J = 0,2) into ΦΦ are investigated in the framework of perturbative quantum chromodynamics (pQCD) and 3P0 quark pair creation model. The results show that these two mechanisms exhibit a quite different behavior in evaluating the decay width for the Xc0 and Xc2. In pQCD method with non-relativistic (NR) approximation, while the calculated Xc2 → ΦΦ decay width is comparable with measured one, the result for the Xc0 → ΦΦ decay width is suppressed and much smaller than experimental value. However, in 3P0 quark pair creation model, the situation is reversed: the decay width of Xc0 → ΦΦ is greatly enhanced and can reproduce the large measured value, while the contribution to the Xc2 → ΦΦ decay width is small. The results suggest that while the pQCD mechanism is the dominant mechanism for Xc2 → ΦΦ decay, the 3P0 quark pair creation mechanism is the dominant one for Xc0 → ΦΦ decay.