Mechanisms for χcJ→ϕϕ\chi_{cJ}\to \phi\phi Decays

Exclusive decays of $\chi_{cJ}(J=0,2)$ into $\phi\phi$ are investigated in the framework of perturbative quantum chromodynamics(pQCD) and \tpz quark pair creation model. The results show that these two mechanisms exhibit a quite different behavior in evaluating the decay width for the $\chi_{c0}$ and $\chi_{c2}$. In pQCD method with nonrelativistic(NR) approximation, while the calculated \cxpp{2} decay width is comparable with measured one, the result for the \cxpp{0} decay width is suppressed and much smaller than experimental value. However, in \tpz quark pair creation model, the situation is reversed: the decay width of \cxpp{0} is greatly enhanced and can reproduce the large measured value, while the contribution to the \cxpp{2} decay width is small. The results suggest that while the pQCD mechanism is the dominant mechanism for \cxpp{2} decay, the \tpz quark pair creation mechanism is the dominant one for \cxpp{0} decay.Comment: 10 pages, 2 figure