Color exchange in near-forward hard elastic scattering

We study the large-t small-angle behavior of quark-quark elastic scattering. We employ a factorization procedure previously developed for fixed-angle scattering, which depends on the color structure of the factorized hard subprocess. We find an evolution in t that (in leading logarithmic approximation) becomes diagonal in a singlet-octet basis in the t-channel as s → ∞. Octet exchange in the hard scattering is associated with the familiar "reggeized", s^αg(t) behavior, which arises from s-dependence in Sudakov suppression. In contrast, Sudakov suppression for t-channel singletexchange in the hard scattering is s-independent. In general, these contributions are mixed by soft corrections, which, however, cancel in many experimental amplitudes and cross sections.