https://doi.org/10.1140/epjc/s2004-02039-4
theoretical physics
The impact factor for the virtual photonto light vector meson transition
1
Sobolev Institute of Mathematics, 630090, Novosibirsk, Russia
2
Budker Institute for Nuclear Physics, 630090, Novosibirsk, Russia
3
Novosibirsk State University, 630090, Novosibirsk, Russia
4
Dipartimento di Fisica, Universitá della Calabria and Istituto Nazionale di Fisica Nucleare, Gruppo collegato di Cosenza, Arcavacata di Rende, 87036, Cosenza, Italy
* e-mail: d-ivanov@math.nsc.ru
We evaluate in the next-to-leading approximation the forward impact factor for the virtual photon to light vector meson transition in the case of longitudinal polarization. We find that in the hard kinematic domain, both in the leading and in the next-to-leading approximation, the expression for the impact factor factorizes, up to power suppressed corrections, into the convolution of a perturbatively calculable hard-scattering amplitude and a meson twist-2 distribution amplitude.
© Springer-Verlag, 2004