Small Gluonic Spots in the Nucleon: Searching for Signatures in Data

Abstract

Nuclear shadowing and color glass condensate are possible only at sufficiently small x where parton clouds of different nucleons overlap in the longitudinal direction. Another condition vital for these effect, an overlap of partons in impact parameters, is not easy to fulfill for gluons which are located within small spots, as follows from the observed weakness of diffractive gluon radiation (smallness of the triple-Pomeron coupling). The predicted weakness of the leading twist gluon shadowing has been confirmed recently by data for J/Psi production and Cronin effect in d-Au collisions at RHIC. Smallness of gluonic spots also leads to a rather low value of the slope of the Pomeron trajectory, confirmed by ZEUS data on elastic photoproduction of J/Psi. At the same time, saturation of unitarity for central pp collisions leads to a substantial increase of the Pomeron slope in good agreement with elastic pp data.

Talk given by B. Povh at the Quark Matter 2004

References in corpus (3)

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• Transparent Nuclei and Deuteron-Gold Collisions at RHIC
• Understanding the Non-Perturbative Deep-Inelastic Scattering: Instanton-induced Inelastic Dipole-Dipole Cross Section

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