Deeply virtual Compton scattering at small x and the access to the GPD H
Abstract
We give a partonic interpretation for the deeply virtual Compton scattering (DVCS) measurements of the H1 and ZEUS Collaborations in the small- x region in terms of generalized parton distributions. Thereby we have a closer look at the skewness effect, parameterization of the t-dependence, revealing the chromomagnetic pomeron, and at a model-dependent access to the anomalous gravitomagnetic moment of nucleon. We also quantify the reparameterization of generalized parton distributions resulting from the inclusion of radiative corrections up to next-to-next-to-leading order. Beyond the leading order approximation, our findings are compatible with a 'holographic' principle that would arise from a (broken) SO(2,1) symmetry. Utilizing our leading-order findings, we also perform a first model-dependent "dispersion relation" fit of HERMES and JLAB DVCS measurements. From that we extract the generalized parton distribution H on its cross-over line and predict the beam charge-spin asymmetry, measurable at COMPASS.
- Publication:
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Nuclear Physics B
- Pub Date:
- December 2010
- DOI:
- arXiv:
- arXiv:0904.0458
- Bibcode:
- 2010NuPhB.841....1K
- Keywords:
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- High Energy Physics - Phenomenology;
- High Energy Physics - Experiment
- E-Print:
- LaTeX, 71 page, 15 figures, Sect. 5 improved, matches published version