Model-independent connections between pion photoproduction and Compton scattering in the. Delta. (1232) region

Journal Article · Wed Jul 01 00:00:00 EDT 1992 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.46.101· OSTI ID:7235424

Benmerrouche, M ^[1]; Mukhopadhyay, N C ^[2]

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1. Department of Physics, Rensselaer Polytechnic Institute, Troy, New York 12180-3590 (United States)
2. Department of Physics, Rensselaer Polytechnic Institute, Troy, New York 12180-3590 (United States) Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195 (United States)

We exploit Grushin {ital et} {ital al}.'s {ital independent} {ital determinations} of the real and the imaginary parts of the pion photoproduction multipoles in the {Delta}(1232) region, without the use of an approximate form of Watson's theorem, and obtain model-independent estimates for the Compton amplitudes for the resonance excitation off nucleons. We compare these with the results obtained from other analyses of photoproduction multipoles. We find the lower bound for the differential cross section using unitarity, and compare our results with available experiments, both the older-generation experiments, primarily at Bonn, and the preliminary results from the recent studies at the Saskatchewan Accelerator Lab. We explore consistency of photoproduction multipoles with the forward Compton scattering amplitude extracted from the measured total hadronic cross sections of photons in hydrogen, using the optical theorem. Finally, we discuss implications for future precision Compton studies of the {Delta}(1232) excitation, in particular, attempts to measure the {ital E}2 to {ital M}1 amplitude ratio, in the nucleon-to-{Delta} electromagnetic transition, which will be feasible at new photon facilities such as the Brookhaven Laser Electron-Gamma Source, exploring the photon polarization observables. These amplitudes contain valuable information on the structure of nucleon and {Delta} baryons, of great topical interest. We vividly demonstrate here the inadequacy of the older generation of Compton scattering experiments, as their poor photon energy resolution and counting statistics limit the quality of physics extractable from the data. This urgently calls for newer-generation {ital high}{minus}{ital statistics} experiments with {ital high} photon energy resolution, using the photon polarization as a powerful tool.

• DOE Contract Number: FG02-88ER40448
• OSTI ID: 7235424
• Journal Information: Physical Review, D (Particles Fields); (United States), Vol. 46:1; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
PHOTON-NUCLEON INTERACTIONS
COMPTON EFFECT
PIONS
PHOTOPRODUCTION
DEEP INELASTIC SCATTERING
DELTA-1232 BARYONS
DIFFERENTIAL CROSS SECTIONS
E2-TRANSITIONS
ENERGY SPECTRA
M1-TRANSITIONS
PHOTONS
POLARIZATION
QUANTUM CHROMODYNAMICS
SCATTERING AMPLITUDES
TOTAL CROSS SECTIONS
UNITARITY
AMPLITUDES
BARYONS
BASIC INTERACTIONS
BOSONS
CROSS SECTIONS
DELTA BARYONS
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ENERGY-LEVEL TRANSITIONS
FERMIONS
FIELD THEORIES
HADRONS
INELASTIC SCATTERING
INTERACTIONS
LEPTON-BARYON INTERACTIONS
LEPTON-HADRON INTERACTIONS
LEPTON-NUCLEON INTERACTIONS
MASSLESS PARTICLES
MESONS
MULTIPOLE TRANSITIONS
N BARYONS
PARTICLE INTERACTIONS
PARTICLE PRODUCTION
PHOTON-BARYON INTERACTIONS
PHOTON-HADRON INTERACTIONS
PSEUDOSCALAR MESONS
QUANTUM FIELD THEORY
SCATTERING
SPECTRA
662330* - Photon & Charged-Lepton Interactions with Hadrons- (1992)
662230 - Quantum Chromodynamics- (1992-)