Recalculation of Proton Compton Scattering in Perturbative QCD

dc.creatorBrooks, Travis
dc.creatorDixon, Lance
dc.date2000-04-15
dc.date2000-10-16
dc.date.accessioned2026-07-07T13:10:39Z
dc.date.available2026-07-07T13:10:39Z
dc.descriptionAt very high energy and wide angles, Compton scattering on the proton (gamma p -> gamma p) is described by perturbative QCD. The perturbative QCD calculation has been performed several times previously, at leading twist and at leading order in alpha_s, with mutually inconsistent results, even when the same light-cone distribution amplitudes have been employed. We have recalculated the helicity amplitudes for this process, using contour deformations to evaluate the singular integrals over the light-cone momentum fractions. We do not obtain complete agreement with any previous result. Our results are closest to those of the most recent previous computation, differing significantly for just one of the three independent helicity amplitudes, and only for backward scattering angles. We present results for the unpolarized cross section, and for three different polarization asymmetries. We compare the perturbative QCD predictions for these observables with those of the handbag and diquark models. In order to reduce uncertainties associated with alpha_s and the three-quark wave function normalization, we have normalized the Compton cross section using the proton elastic form factor. The theoretical predictions for this ratio are about an order of magnitude below existing experimental data.
dc.descriptionLatex, 23 pages, 13 figures. Checked numerical integration one more way; added results for one more proton distribution amplitude; a few other minor changes. Version to appear in Phys. Rev. D
dc.identifierhttps://arxiv.org/abs/hep-ph/0004143
dc.identifierhttp://arxiv.org/abs/hep-ph/0004143
dc.identifierPhys.Rev.D62:114021,2000
dc.identifierdoi:10.1103/PhysRevD.62.114021
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/229065
dc.subjectHigh Energy Physics - Phenomenology
dc.titleRecalculation of Proton Compton Scattering in Perturbative QCD
dc.typetext

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