Going beyond the peaking approximation in the PQCD analysis of exclusive heavy meson pair production

Abstract

In the PQCD analyses of the exclusive production of higher generation hadrons, the quark distribution amplitude of the heavy quark system has often been approximated by a {delta} function from the nonrelativistic consideration. Going beyond the peaking approximation, the factorization of the covariant hard scattering amplitude from the nonperturbative quark distribution amplitude is no longer valid. We therefore use the light-cone time-ordered perturbation theory which is the step prior to the usual factorization formula and calculate the form factor of a pseudoscalar meson composed of a heavy quark and antiquark. However, we find that the numerical results for the cross section of exclusive heavy meson pair production in e{sup +}e{sup {minus}} annihilation are not much different from those of the peaking approximation. {copyright} {ital 1997} {ital The American Physical Society}