High-energy photon-nucleon and photon-nucleus cross sections
- Department of Physics, University of Wisconsin enMadison, Madison, Wisconsin 53706 (United States)
- Department of Physics, Texas A M University, College Station, Texas 77843 (United States)
- Department of Theoretical Physics, University of Lund, Lund, Sweden S-22362 ( )
- 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), Vol. 48:3; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
Similar Records
Hadron production in photon-photon collisions. [Cross sections, structure functions, light cone, parton and vector dominance model, sum rules, helicity analysis, quark model, scaling]
Photon-hadron interactions in relativistic heavy ion collisions
Related Subjects
PHOTON-NUCLEON INTERACTIONS
CROSS SECTIONS
INELASTIC SCATTERING
COSMIC RADIATION
DESY
DISTRIBUTION FUNCTIONS
EIKONAL APPROXIMATION
GLUONS
PHOTON-PROTON INTERACTIONS
PHOTONUCLEAR REACTIONS
PROBABILITY
QUANTUM CHROMODYNAMICS
QUARK MODEL
ACCELERATORS
BASIC INTERACTIONS
BOSONS
COMPOSITE MODELS
CYCLIC ACCELERATORS
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
FIELD THEORIES
FUNCTIONS
INTERACTIONS
IONIZING RADIATIONS
MATHEMATICAL MODELS
NUCLEAR REACTIONS
PARTICLE INTERACTIONS
PARTICLE MODELS
PHOTON-BARYON INTERACTIONS
PHOTON-HADRON INTERACTIONS
POSTULATED PARTICLES
QUANTUM FIELD THEORY
RADIATIONS
SCATTERING
SYNCHROTRONS
662330* - Photon & Charged-Lepton Interactions with Hadrons- (1992)