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Title: Semi-exclusive deeply virtual Compton scattering

Abstract

We consider Semi-Exclusive Deeply Virtual Compton Scattering, {gamma}*p{yields}{gamma}Y (SECS), where Y is an inclusive state of intermediate mass, {lambda}{sub QCD}<<m{sub Y}<<Q. When the photon is produced with a large transverse momentum k{sub perpendicular}{approx}m{sub Y} the subprocess is hard and the struck quark fragments independently of the target spectators. Using completeness this allows us to express the SECS cross section in terms of ordinary parton distributions. Apart from direct comparisons with data (yet to come) new information on Bloom-Gilman duality may be obtained through comparisons of resonance production via DVCS ({gamma}*p{yields}{gamma}N*) with the SECS scaling distribution in m{sub Y}.

Authors:
;  [1]
  1. Department of Physical Sciences and Helsinki Institute of Physics POB 64, FIN-00014 University of Helsinki (Finland)
Publication Date:
OSTI Identifier:
21020324
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 7; Other Information: DOI: 10.1103/PhysRevD.75.077502; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COMPARATIVE EVALUATIONS; COMPTON EFFECT; CROSS SECTIONS; DISTRIBUTION; DUALITY; PHOTON-PROTON INTERACTIONS; PHOTONS; QUANTUM CHROMODYNAMICS; QUARKS; TRANSVERSE MOMENTUM

Citation Formats

Hoyer, Paul, and Virtanen, Heidi. Semi-exclusive deeply virtual Compton scattering. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.077502.
Hoyer, Paul, & Virtanen, Heidi. Semi-exclusive deeply virtual Compton scattering. United States. doi:10.1103/PHYSREVD.75.077502.
Hoyer, Paul, and Virtanen, Heidi. Sun . "Semi-exclusive deeply virtual Compton scattering". United States. doi:10.1103/PHYSREVD.75.077502.
@article{osti_21020324,
title = {Semi-exclusive deeply virtual Compton scattering},
author = {Hoyer, Paul and Virtanen, Heidi},
abstractNote = {We consider Semi-Exclusive Deeply Virtual Compton Scattering, {gamma}*p{yields}{gamma}Y (SECS), where Y is an inclusive state of intermediate mass, {lambda}{sub QCD}<<m{sub Y}<<Q. When the photon is produced with a large transverse momentum k{sub perpendicular}{approx}m{sub Y} the subprocess is hard and the struck quark fragments independently of the target spectators. Using completeness this allows us to express the SECS cross section in terms of ordinary parton distributions. Apart from direct comparisons with data (yet to come) new information on Bloom-Gilman duality may be obtained through comparisons of resonance production via DVCS ({gamma}*p{yields}{gamma}N*) with the SECS scaling distribution in m{sub Y}.},
doi = {10.1103/PHYSREVD.75.077502},
journal = {Physical Review. D, Particles Fields},
number = 7,
volume = 75,
place = {United States},
year = {Sun Apr 01 00:00:00 EDT 2007},
month = {Sun Apr 01 00:00:00 EDT 2007}
}
  • We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized He-4 gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling He-4 nuclei.more » We measure beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a model-independent way, the real and imaginary parts of the only He-4 Compton form factor, HA. This first measurement of coherent deeply virtual Compton scattering on the He-4 nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.« less
  • In this work we estimate the differential cross section for the high energy deeply virtual Compton scattering on a photon target, {gamma}*{gamma}{yields}{gamma}{gamma}, within the QCD dipole-dipole scattering formalism. For the phenomenology, a saturation model for the dipole-dipole cross section for two photon scattering is considered. Its robustness is supported by a good description of current accelerator data. In addition, we consider the related exclusive vector meson production processes, {gamma}*{gamma}{yields}V{gamma}. This analysis is focused on the light {rho} and {phi} meson production, which produces larger cross sections. The phenomenological results are compared with the theoretical calculation using the color-dipole Balitsky-Fadin-Kuraev-Lipatov approach.
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