2008/12/02 by Stanley J. Brodsky, Felipe J. Llanes-Estrada, Felipe J. Llanes–Estrada +1
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.79.033012
published as Phys.Rev.D79:033012,2009 · 20 pages, 15 figures
arxiv created 2008/12/02 · openalex publication_date 2009/02/20 · arxiv updated 2014/11/18 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The local coupling of two photons to the fundamental quark currents of a hadron gives an energy-independent contribution to the Compton amplitude proportional to the charge squared of the struck quark, a contribution which has no analog in hadron scattering reactions. We show that this local contribution has a real phase and is universal, giving the same contribution for real or virtual Compton scattering for any photon virtuality and skewness at fixed momentum transfer squared t. The t dependence of this J=0 fixed Regge pole is parameterized by a yet unmeasured even charge-conjugation form factor of the target nucleon. The t=0 limit gives an important constraint on the dependence of the nucleon mass on the quark mass through the Weisberger relation. We discuss how this 1/x form factor can be extracted from high-energy deeply virtual Compton scattering and examine predictions given by models of the H generalized parton distribution.