High-energy photon-nucleon and photon-nucleus cross sections

Journal Article · Sun Aug 01 04:00:00 EDT 1993 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.48.1048· OSTI ID:7368810

Honjo, K; Durand, L ^[1]; Gandhi, R ^[2]; Pi, H ^[3]; Sarcevic, I ^[4]

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1. Department of Physics, University of Wisconsin enMadison, Madison, Wisconsin 53706 (United States)
2. Department of Physics, Texas A M University, College Station, Texas 77843 (United States)
3. Department of Theoretical Physics, University of Lund, Lund, Sweden S-22362 ( )
4. Department of Physics, University of Arizona, Tucson, Arizona 85721 (United States)

We reexamine the theory of hadronic photon-nucleon interactions at the quark-gluon level. The possibility of multiple parton collisions in a single photon-nucleon collision requires an eikonal treatment of the high-energy scattering process. We give a general formulation of the theory in which the [gamma][ital p] cross section is expressed as a sum over properly eikonalized cross sections for the interaction of the virtual hadronic components of the photon with the proton, with each cross section weighted by the probability with which that component appears in the photon, and then develop a detailed model which includes contributions from light vector mesons and from excited virtual states described in a quark-gluon basis. The parton distribution functions which appear can be related approximately to those in the pion, while a weighted sum gives the distribution functions for the photon. We use the model to make improved QCD-based predictions for the total inelastic photon-nucleon and photon-nucleus cross sections at energies relevant for DESY HERA experiments and cosmic-ray observations. We emphasize the importance in this procedure of including a soft-scattering background such that the calculated cross sections join smoothly with low-energy data. Our results show clearly that high-energy measurements of the total inelastic [gamma][ital p] cross section can impose strong constraints on the gluon and quark distributions in the photon, and indirectly on those in the pion.

• DOE Contract Number: AC02-76ER00881; FG02-85ER40213
• OSTI ID: 7368810
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 48:3; ISSN 0556-2821; ISSN PRVDAQ
• Country of Publication: United States
• Language: English

Related Subjects

662330* -- Photon & Charged-Lepton Interactions with Hadrons-- (1992)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCELERATORS
BASIC INTERACTIONS
BOSONS
COMPOSITE MODELS
COSMIC RADIATION
CROSS SECTIONS
CYCLIC ACCELERATORS
DESY
DISTRIBUTION FUNCTIONS
EIKONAL APPROXIMATION
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
FIELD THEORIES
FUNCTIONS
GLUONS
INELASTIC SCATTERING
INTERACTIONS
IONIZING RADIATIONS
MATHEMATICAL MODELS
NUCLEAR REACTIONS
PARTICLE INTERACTIONS
PARTICLE MODELS
PHOTON-BARYON INTERACTIONS
PHOTON-HADRON INTERACTIONS
PHOTON-NUCLEON INTERACTIONS
PHOTON-PROTON INTERACTIONS
PHOTONUCLEAR REACTIONS
POSTULATED PARTICLES
PROBABILITY
QUANTUM CHROMODYNAMICS
QUANTUM FIELD THEORY
QUARK MODEL
RADIATIONS
SCATTERING
SYNCHROTRONS