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Title: Deeply virtual Compton scattering: How to test handbag dominance?

Abstract

We propose detailed tests of the handbag approximation in exclusive deeply virtual Compton scattering. Those tests make no use of any prejudice about parton correlations in the proton which are basically unknown objects and beyond the scope of perturbative QCD. Since important information on the proton substructure can be gained in the regime of light cone dominance we consider that such a class of tests is of special relevance.

Authors:
 [1];  [2];  [3];  [2];  [3];  [4]
  1. NIKHEF, P.O. Box 41882, 1009 DB Amsterdam (Netherlands)
  2. (France)
  3. CPhT, Ecole Polytechnique, 91128 Palaiseau (France)
  4. Dept. of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045 (United States)
Publication Date:
OSTI Identifier:
21199138
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 432; Journal Issue: 1; Conference: 7. international conference on hadron spectroscopy, Upton, NY (United States), 25-30 Aug 1997; Other Information: DOI: 10.1063/1.56099; (c) 1998 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; APPROXIMATIONS; COMPTON EFFECT; CORRELATIONS; GLUONS; HELICITY; LIGHT CONE; PERTURBATION THEORY; PROTONS; QUANTUM CHROMODYNAMICS; QUARK-ANTIQUARK INTERACTIONS; QUARKS; S MATRIX

Citation Formats

Gousset, T., SUBATECH, B.P. 20722, 44307 Nantes Cedex 3, Diehl, M., DAPNIA/SPhN, C.E. Saclay, 91191 Gif sur Yvette, Pire, B., and Ralston, J. P.. Deeply virtual Compton scattering: How to test handbag dominance?. United States: N. p., 1998. Web. doi:10.1063/1.56099.
Gousset, T., SUBATECH, B.P. 20722, 44307 Nantes Cedex 3, Diehl, M., DAPNIA/SPhN, C.E. Saclay, 91191 Gif sur Yvette, Pire, B., & Ralston, J. P.. Deeply virtual Compton scattering: How to test handbag dominance?. United States. doi:10.1063/1.56099.
Gousset, T., SUBATECH, B.P. 20722, 44307 Nantes Cedex 3, Diehl, M., DAPNIA/SPhN, C.E. Saclay, 91191 Gif sur Yvette, Pire, B., and Ralston, J. P.. Fri . "Deeply virtual Compton scattering: How to test handbag dominance?". United States. doi:10.1063/1.56099.
@article{osti_21199138,
title = {Deeply virtual Compton scattering: How to test handbag dominance?},
author = {Gousset, T. and SUBATECH, B.P. 20722, 44307 Nantes Cedex 3 and Diehl, M. and DAPNIA/SPhN, C.E. Saclay, 91191 Gif sur Yvette and Pire, B. and Ralston, J. P.},
abstractNote = {We propose detailed tests of the handbag approximation in exclusive deeply virtual Compton scattering. Those tests make no use of any prejudice about parton correlations in the proton which are basically unknown objects and beyond the scope of perturbative QCD. Since important information on the proton substructure can be gained in the regime of light cone dominance we consider that such a class of tests is of special relevance.},
doi = {10.1063/1.56099},
journal = {AIP Conference Proceedings},
number = 1,
volume = 432,
place = {United States},
year = {Fri May 29 00:00:00 EDT 1998},
month = {Fri May 29 00:00:00 EDT 1998}
}
  • We propose detailed tests of the handbag approximation in exclusive deeply virtual Compton scattering. Those tests make no use of any prejudice about parton correlations in the proton which are basically unknown objects and beyond the scope of perturbative QCD. Since important information on the proton substructure can be gained in the regime of light cone dominance we consider that such a class of tests is of special relevance. {copyright} {ital 1998 American Institute of Physics.}
  • We consider Deeply Virtual Compton Scattering (DVCS) on nucleons and nuclei in the framework of generalized vector meson dominance (GVMD) model. We demonstrate that the GVMD model provides a good description of the HERA data on the dependence of the proton DVCS cross section on $Q^2$, $W$ (at $Q^2=4$ GeV$^2$) and $t$. At $Q^2 = 8$ GeV$^2$, the soft $W$-behavior of the GVMD model somewhat underestimates the $W$-dependence of the DVCS cross section due to the hard contribution not present in the GVMD model. We estimate $1/Q^2$ power-suppressed corrections to the DVCS amplitude and the DVCS cross section and findmore » them large. We also make predictions for the nuclear DVCS amplitude and cross section in the kinematics of the future Electron-Ion Collider. We predict significant nuclear shadowing, which matches well predictions of the leading-twist nuclear shadowing in DIS on nuclei.« less
  • In the framework of generalized parton distributions, we study the helicity-dependent and independent cross sections measured in Hall A and the beam spin asymmetries measured in Hall B at Jefferson Laboratory. We perform a global fit of these data and fits on each kinematic bin. We extract the real and imaginary parts of the Compton form factor H under the main hypothesis of dominance of the generalized parton distribution H and twist 2 accuracy. We discuss our results and compare to previous extractions as well as to the VGG model. We pay extra attention to the estimation of errors onmore » the extraction of H.« less
  • We show that factorization holds for the deeply virtual Compton scattering amplitude in QCD, up to power suppressed terms, to all orders in perturbation theory. The theorem applies to the production of off-shell photons as well as real photons. We give a detailed treatment of the situation where one of the two partons joining the parton density to the hard scattering has zero longitudinal momentum. {copyright} {ital 1999} {ital The American Physical Society}
  • We show that the one-loop QCD correction to deeply virtual Compton scattering can be factorized into finite perturbative contributions and collinearly divergent terms, which correspond to the matrix elements of the off-forward parton distributions. As a by-product, we obtain the next-to-leading order coefficient functions in the generalized operator product expansion of two vector currents. {copyright} {ital 1997} {ital The American Physical Society}