Leading twist nuclear shadowing, nuclear generalized parton distributions and nuclear DVCS at small x

Abstract

We generalize the leading twist theory of nuclear shadowing and calculate quark and gluon generalized parton distributions (GPDs) of spinless nuclei. We predict very large nuclear shadowing for nuclear GPDs. In the limit of the purely transverse momentum transfer, our nuclear GPDs become impact-parameter-dependent nuclear parton distributions (PDFs). Nuclear shadowing induces nontrivial correlations between the impact parameter b and the light-cone fraction x. We make predictions for the deeply virtual Compton scattering (DVCS) amplitude and the DVCS cross section on Pb-208 at high energies. We calculate the cross section of the Bethe-Heitler (BH) process and address the issue of the extraction of the DVCS signal from the e A \to e γA cross section. We find that the e A \to e γA differential cross section is dominated by DVCS at the momentum transfer t near the minima of the nuclear form factor. We also find that nuclear shadowing leads to dramatic oscillations of the DVCS beam-spin asymmetry, A_{LU}, as a function of t. The position of the points where A_{LU} changes sign is directly related to the magnitude of nuclear shadowing.

37 pages, 12 figures. Matches the published version, Phys. Rev. 79, 035210 (2009)

References in corpus (7)

• The Physics of Ultraperipheral Collisions at the LHC
• Can one measure timelike Compton scattering at LHC ?
• On the mistake in the implementation of the minimal model of the dual parameterization and resulting inability to describe the high-energy DVCS data
• Neutron contribution to nuclear DVCS asymmetries
• Exclusive photoproduction of lepton pairs at LHC
• Deeply Virtual Compton Scattering on nucleons and nuclei in generalized vector meson dominance model
• Generalized parton distributions of few body systems