Unitarity cutting rules for the nucleus excitation and topological cross sections in hard production off nuclei from nonlinear k_t-factorization
| Autor: | Nikolaev, N. N., Schäfer, W. |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
perturbation theory [quantum chromodynamics]
jet [quark] multiple [exchange] Nuclear Theory pair production [jet] diffraction FOS: Physical sciences dipole [color] Nuclear Theory (nucl-th) deep inelastic scattering [p nucleus] hard scattering High Energy Physics - Phenomenology (hep-ph) charm [quark] jet [gluon] unitarity ddc:530 Nuclear Experiment (nucl-ex) Nuclear Experiment channel cross section long-range [correlation] High Energy Physics::Phenomenology multiplicity [hadron] bibliography fragmentation [target] collective phenomena High Energy Physics - Phenomenology coupled channel [model] Regge [field theory] color [expansion 1/N] hadroproduction [jet] factorization [transverse momentum] exchange [pomeron] nonlinear High Energy Physics::Experiment correlation [rapidity] S-matrix |
| Zdroj: | Physical review / D 74(7), 074021 (2006). doi:10.1103/PhysRevD.74.074021 |
| DOI: | 10.48550/arxiv.hep-ph/0607307 |
| Popis: | At the partonic level, a typical final state in small-x deep inelastic scattering off nuclei and hard proton-nucleus collisions can be characterized by the multiplicity of color-excited nucleons. Within reggeon field theory, each color-excited nucleon is associated with the unitarity cut of the pomeron exchanged between the projectile and nucleus. In this communication we derive the unitarity rules for the multiplicity of excited nucleons, alias cut pomerons, alias topological cross sections, for typical hard dijet production processes. We demonstrate how the coupled-channel non-Abelian intranuclear evolution of color dipoles, inherent to pQCD, gives rise to the reggeon field theory diagrams for final states in terms of the uncut, and two kinds of cut, pomerons. Upon the proper identification of the uncut and cut pomeron exchanges, the topological cross sections for dijet production follow in a straightforward way from the earlier derived nonlinear k_t - factorization quadratures for the inclusive dijet cross sections. The concept of a coherent (collective) nuclear glue proves extremely useful for the formulation of reggeon field theory vertices of multipomeron - cut and uncut - couplings to particles and between themselves. A departure of our unitarity cutting rules from the ones suggested by the pre-QCD Abramovsky-Kancheli-Gribov rules, stems from the coupled-channel features of intranuclear pQCD. We propose a multiplicity re-summation as a tool for the isolation of topological cross sections for single-jet production. Comment: 53 pages, 16 eps-figures, to appear in Phys. Rev. D |
| Databáze: | OpenAIRE |
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