Subprocess Size in Hard Exclusive Scattering
Abstract
The interaction region of hard exclusive hadron scattering can have a large transverse size due to endpoint contributions, where one parton carries most of the hadron momentum. The endpoint region is enhanced and can dominate in processes involving multiple scattering and quark helicity flip. The endpoint Fock states have perturbatively short lifetimes and scatter softly in the target. We give plausible arguments that endpoint contributions can explain the apparent absence of color transparency in fixed angle exclusive scattering and the dimensional scaling of transverse rho photoproduction at high momentum transfer, which requires quark helicity flip. We also present a quantitative estimate of Sudakov effects.
Cite
@article{arxiv.hep-ph/0210124,
title = {Subprocess Size in Hard Exclusive Scattering},
author = {P. Hoyer and J. T. Lenaghan and K. Tuominen and C. Vogt},
journal= {arXiv preprint arXiv:hep-ph/0210124},
year = {2011}
}
Comments
16 pages, 4 figures, JHEP style; v2: quantitative estimate of Sudakov effects and more detailed discussion of endpoint behaviour of meson distribution amplitude added, few other clarifications, version to appear in Phys. Rev. D