Virtual photon fragmentation functions - art. no. 074007

We introduce operator definitions for virtual photon fragmentation function s, which are needed for reliable calculations of Drell-Yan transverse momen tum (Q(T)) distributions when Q(T) is much larger than the invariant mass Q . We derive the evolution equations for these fragmentation functions. We c alculate the leading order evolution kernels for partons to fragment into a n unpolarized as well as a polarized virtual photon. We find that fragmenta tion functions to a longitudinally polarized virtual photon are most import ant at small z, and the fragmentation functions to a transversely polarized virtual photon dominate the large z region. We discuss the implications of this finding to the J/psi mesons' polarization at large transverse momentu m.