Cao, FG , Massey Univ, Inst Fundamental Sci, Private Bag 11 222, Palmerston North, New Zealand.
部门归属:
Massey Univ, Inst Fundamental Sci, Palmerston North, New Zealand; CCAST, World Lab, Beijing 100080, Peoples R China; Acad Sinica, Inst High Energy Phys, Beijing 100039, Peoples R China; Acad Sinica, Inst Theoret Phys, Beijing 100080, Peoples R China
英文摘要:
The large-Q(2) behavior of eta(c)-gamma and eta(b)-gamma transition form factors F-eta c gamma(Q(2)) and F-eta b gamma(Q(2)) is analyzed in the framework of light-cone perturbative QCD with heavy quark (c and b) mass effects, parton transverse momentum dependence, and higher helicity components in the light-cone wave function are respected. It is pointed out that the quark mass effect brings significant modifications to the asymptotic predictions of the transition form factors in a rather broad energy region, and the modification for F-eta b gamma(Q(2)) is much more severe than that for F-eta c gamma(Q(2)) due to the b quark being heavier than the c quark. The parton transverse momentum and the higher helicity components also play a role in reducing the perturbative predictions. For the transition form factor F-eta c gamma(Q(2)), they bring sizable corrections in the present experimentally accessible energy region (Q(2) less than or equal to 10 GeV2). For the transition form factor F-eta b gamma(Q(2)), the corrections coming from these two factors are negligible since the b-quark mass is much larger than the parton's average transverse momentum. The coming e(+)e(-) collider (CERN LEP2) will provide the opportunity to examine these theoretical predictions. [S0556-2821(99)00909-1].
Cao, FG,Huang, T. Large corrections to asymptotic F-eta c gamma and F-eta b gamma in the light-cone perturbative QCD[J]. PHYSICAL REVIEW D,1999,59(9):-.
