PROTON-PROTON NEAR-FORWARD HARD ELASTIC-SCATTERING

We calculate the leading twist contribution to near-forward proton-proton (and proton-antiproton) elastic scattering with large momentum transfer, in the multiple scattering (Landshoff) mechanism. The near-forward amplitude in this perturbative approach is dominated by singlet exchange for all three valence quark-quark scatterings. We assume the existence of a hard singlet quark-quark amplitude, which we estimate to be O(alpha(s)(2)/t). For a three-quark state whose transverse size is less than 1/Lambda(QCD), Sudakov resummation accounts for both approximate d sigma(pp)/dt similar to t(-8) at moderate t, and d sigma(pp)/dt similar to t(-10) at larger t. The transition from approximate t(-8) to t(-10) behavior is strongly correlated with the transverse size of the valence three-quark state in the proton.