Gauge invariance and Compton scattering from relativistic composite systems

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.48.1948· OSTI ID:6040022

Ito, H ^[1]; Gross, F ^[2]

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1. Center for Nuclear Study, Department of Physics, George Washington University, Washington, D.C. 20052 (United States)
2. Continuous Electron Beam Accelerator Facility, 12000 Jefferson Avenue, Newport News, Virginia 23606 (United States) Physics Department, College of William Mary, Williamsburg, Virginia 23185 (United States)

Using the Ward-Takahashi (WT) identity and the Bethe-Salpeter wave equation, we investigate the dynamical requirements imposed by electromagnetic gauge invariance on Compton scattering from relativistic composite systems. The importance of off-shell rescattering in intermediate states, which is equivalent to final state interactions in inclusive processes, is clarified in the context of current conservation. It is shown that, if the nuclear force is nonlocal, there will be both two-photon interaction currents and rescattering contributions to terms involving one-photon interaction currents. We derive the two-body WT identity for the two-photon interaction currents, and obtain explicit forms for the interaction current operators for three illustrative models of nuclear forces: (a) two-pion exchange forces with baryon resonances, (b) covariant separable forces, and (c) charged one-pion exchange.

• DOE Contract Number: FG05-86ER40270; FG05-88ER40435
• OSTI ID: 6040022
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 48:4; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

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663300* -- Nuclear Reactions & Scattering
General-- (1992-)
663410 -- Photonuclear Reactions & Photon Scattering-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BASIC INTERACTIONS
BETHE-SALPETER EQUATION
COMPTON EFFECT
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ENERGY RANGE
EQUATIONS
GAUGE INVARIANCE
INTERACTIONS
INVARIANCE PRINCIPLES
NUCLEAR FORCES
RELATIVISTIC RANGE
SCATTERING
WARD IDENTITY