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Title: Deeply virtual Compton scattering at 6 GeV

Abstract

The authors propose a measurement of the Deep Virtual Compton Scattering process (DVCS) ep {yields} ep{gamma} in Hall A at Jefferson Lab with a 6 GeV beam. The authors are able to explore the onset of Q{sup 2} scaling, by measuring a beam helicity asymmetry for Q{sup 2} ranging from 1.5 to 2.5 GeV{sup 2} at x{sub B} {approx} 0.35. At this kinematics, the asymmetry is dominated by the DVCS Bethe-Heitler (BH) interference, which is proportional to the imaginary part of the DVCS amplitude amplified by the full magnitude of the BH amplitude. The imaginary part of the DVCS amplitude is expected to scale early. Indeed, the imaginary part of the forward Compton amplitude measured in deep inelastic scattering (via the optical theorem) scales at Q{sup 2} as low as 1 GeV{sup 2}. If the scaling regime is reached, they make an 8% measurement of the skewed parton distributions (SPD) contributing to the DVCS amplitude. Also, this experiment allows them to separately estimate the size of the higher-twist effects, since they are only suppressed by an additional factor 1/Q compared to the leading-twist term, and have a different angular dependence. They use a polarized electron beam and detect the scatteredmore » electron in the HRSe, the real photon in an electromagnetic calorimeter (under construction) and the recoil proton in a shielded scintillator array (to be constructed). This allows them to determine the difference in cross-sections for electrons of opposite helicities. This observable is directly linked to the SPD's. The authors estimate that 25 days of beam (600 hours) are needed to achieve this goal.« less

Authors:
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Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA (US)
Sponsoring Org.:
USDOE Office of Energy Research (ER) (US)
OSTI Identifier:
835025
Report Number(s):
JLAB-PHY-00-79; DOE/ER/40150-3033
TRN: US0407424
DOE Contract Number:  
AC05-84ER40150
Resource Type:
Journal Article
Resource Relation:
Other Information: No journal information given for this preprint; PBD: 1 Jun 2000
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AMPLITUDES; ASYMMETRY; CALORIMETERS; COMPTON EFFECT; CONSTRUCTION; CROSS SECTIONS; DEEP INELASTIC SCATTERING; ELECTRON BEAMS; ELECTRONS; HELICITY; OPTICAL THEOREM; PARTONS; PHOSPHORS; PHOTONS; PROTONS

Citation Formats

Jian-ping Chen, Eugene Chudakov, Cornelis De Jager, Javier Gomez, Jens-ole Hansen, John Lerose, Robert Michaels, Joseph Mitchell, Arunava Saha, Bogdan Wojtsekhowski, J. Berthot, Pierre Bertin, Alexandre Deur, Rachele Di Salvo, Lawrence Weinstein, Werner Boeglin, Pete Markowitz, Jeffrey Templon, Paul Gueye, Ting Chang, Alan Nathan, Raffaele De Leo, Luigi Lagamba, Moskov Amarian, Evaristo Cisbani, Salvatore Frullani, Franco Garibaldi, R. Iommi, Mauro Iodice, Guido Urciuoli, Marc Vanderhaeghen, Douglas Higinbotham, Xiaodong Jiang, Pierre Guichon, Yves Roblin, Gail Dodge, Christophe Jutier, Charles Hyde-wright, Franck Sabatie, Luminita Todor, and Paul Ulmer. Deeply virtual Compton scattering at 6 GeV. United States: N. p., 2000. Web.
Jian-ping Chen, Eugene Chudakov, Cornelis De Jager, Javier Gomez, Jens-ole Hansen, John Lerose, Robert Michaels, Joseph Mitchell, Arunava Saha, Bogdan Wojtsekhowski, J. Berthot, Pierre Bertin, Alexandre Deur, Rachele Di Salvo, Lawrence Weinstein, Werner Boeglin, Pete Markowitz, Jeffrey Templon, Paul Gueye, Ting Chang, Alan Nathan, Raffaele De Leo, Luigi Lagamba, Moskov Amarian, Evaristo Cisbani, Salvatore Frullani, Franco Garibaldi, R. Iommi, Mauro Iodice, Guido Urciuoli, Marc Vanderhaeghen, Douglas Higinbotham, Xiaodong Jiang, Pierre Guichon, Yves Roblin, Gail Dodge, Christophe Jutier, Charles Hyde-wright, Franck Sabatie, Luminita Todor, & Paul Ulmer. Deeply virtual Compton scattering at 6 GeV. United States.
Jian-ping Chen, Eugene Chudakov, Cornelis De Jager, Javier Gomez, Jens-ole Hansen, John Lerose, Robert Michaels, Joseph Mitchell, Arunava Saha, Bogdan Wojtsekhowski, J. Berthot, Pierre Bertin, Alexandre Deur, Rachele Di Salvo, Lawrence Weinstein, Werner Boeglin, Pete Markowitz, Jeffrey Templon, Paul Gueye, Ting Chang, Alan Nathan, Raffaele De Leo, Luigi Lagamba, Moskov Amarian, Evaristo Cisbani, Salvatore Frullani, Franco Garibaldi, R. Iommi, Mauro Iodice, Guido Urciuoli, Marc Vanderhaeghen, Douglas Higinbotham, Xiaodong Jiang, Pierre Guichon, Yves Roblin, Gail Dodge, Christophe Jutier, Charles Hyde-wright, Franck Sabatie, Luminita Todor, and Paul Ulmer. Thu . "Deeply virtual Compton scattering at 6 GeV". United States. https://www.osti.gov/servlets/purl/835025.
@article{osti_835025,
title = {Deeply virtual Compton scattering at 6 GeV},
author = {Jian-ping Chen and Eugene Chudakov and Cornelis De Jager and Javier Gomez and Jens-ole Hansen and John Lerose and Robert Michaels and Joseph Mitchell and Arunava Saha and Bogdan Wojtsekhowski and J. Berthot and Pierre Bertin and Alexandre Deur and Rachele Di Salvo and Lawrence Weinstein and Werner Boeglin and Pete Markowitz and Jeffrey Templon and Paul Gueye and Ting Chang and Alan Nathan and Raffaele De Leo and Luigi Lagamba and Moskov Amarian and Evaristo Cisbani and Salvatore Frullani and Franco Garibaldi and R. Iommi and Mauro Iodice and Guido Urciuoli and Marc Vanderhaeghen and Douglas Higinbotham and Xiaodong Jiang and Pierre Guichon and Yves Roblin and Gail Dodge and Christophe Jutier and Charles Hyde-wright and Franck Sabatie and Luminita Todor and Paul Ulmer},
abstractNote = {The authors propose a measurement of the Deep Virtual Compton Scattering process (DVCS) ep {yields} ep{gamma} in Hall A at Jefferson Lab with a 6 GeV beam. The authors are able to explore the onset of Q{sup 2} scaling, by measuring a beam helicity asymmetry for Q{sup 2} ranging from 1.5 to 2.5 GeV{sup 2} at x{sub B} {approx} 0.35. At this kinematics, the asymmetry is dominated by the DVCS Bethe-Heitler (BH) interference, which is proportional to the imaginary part of the DVCS amplitude amplified by the full magnitude of the BH amplitude. The imaginary part of the DVCS amplitude is expected to scale early. Indeed, the imaginary part of the forward Compton amplitude measured in deep inelastic scattering (via the optical theorem) scales at Q{sup 2} as low as 1 GeV{sup 2}. If the scaling regime is reached, they make an 8% measurement of the skewed parton distributions (SPD) contributing to the DVCS amplitude. Also, this experiment allows them to separately estimate the size of the higher-twist effects, since they are only suppressed by an additional factor 1/Q compared to the leading-twist term, and have a different angular dependence. They use a polarized electron beam and detect the scattered electron in the HRSe, the real photon in an electromagnetic calorimeter (under construction) and the recoil proton in a shielded scintillator array (to be constructed). This allows them to determine the difference in cross-sections for electrons of opposite helicities. This observable is directly linked to the SPD's. The authors estimate that 25 days of beam (600 hours) are needed to achieve this goal.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {6}
}