Proton-Proton Near-Forward Hard Elastic Scattering

Abstract

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 amplitude in the near-forward region 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 $\mathcal{O}({\alpha }_s^2/t)$. For a three-quark state whose transverse size is less than $1/{\Lambda }_{\mathrm{QCD}}$, Sudakov resummation accounts for both approximate $\text{d}{\sigma }^{pp}/\text{d}t\sim t^{-8}$ at moderate $t$, and $\text{d}{\sigma }^{pp}/\text{d}t\sim t^{-10}$ 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.

Comments: 34 pages, LaTeX