Unitary, gauge invariant, relativistic resonance model for pion photoproduction

Journal Article · Wed May 01 04:00:00 EDT 1996 · Physical Review, C

DOI:https://doi.org/10.1103/PhysRevC.53.2422· OSTI ID:283980

Surya, Y ^[1]; Gross, F ^[1]

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1. College of William and Mary, Williamsburg, Virginia 23185 (United States)

Pion photoproduction up to 770 MeV photon laboratory energy is described by a manifestly covariant wave equation, which includes a treatment of the final state {pi}{ital N} interactions consistent with the covariant, unitary, resonance model of {pi}{ital N} scattering previously developed. The kernel of the equation includes nucleon ({ital N}), Roper ({ital N}{sup {asterisk}}), delta ({Delta}), and {ital D}{sub 13} poles and their crossed poles, as well as {pi}, {rho}, and {omega} exchange terms. The Kroll-Rudermann term and other interaction currents ensure that the model is exactly gauge invariant to all orders in the strong coupling {ital g}{sub {pi}{ital NN}}. The threshold value of the {ital E}{sub 0+} amplitude is in good agreement with recent estimates obtained from chiral perturbation theory. Elastic unitarity to first order in the charge {ital e} (Watson theorem) is maintained up to the two-pion production threshold. The complete development of this model, which gives a good fit to all {ital L}{le}2 multiples up to 770 MeV, is presented. {copyright} {ital 1996 The American Physical Society.}

• DOE Contract Number: FG05-88ER40435
• OSTI ID: 283980
• Journal Information: Physical Review, C, Journal Name: Physical Review, C Journal Issue: 5 Vol. 53; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
COUPLING
FINAL-STATE INTERACTIONS
GAUGE INVARIANCE
MEV RANGE 100-1000
PERTURBATION THEORY
PHOTOPRODUCTION
PIONS
RELATIVISTIC RANGE
RESONANCE
UNITARITY
WAVE FUNCTIONS