Gauge-invariant tree-level photoproduction amplitudes with form factors

Journal Article · Wed Jul 01 04:00:00 EDT 1998 · Physical Review, C

DOI:https://doi.org/10.1103/PhysRevC.58.R40· OSTI ID:638833

Haberzettl, H; Bennhold, C; Mart, T ^[1]; Mart, T ^[2]; Feuster, T ^[3]

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1. Center for Nuclear Studies, Department of Physics, The George Washington University, Washington, D.C. 20052 (United States)
2. Jurusan Fisika, FMIPA, Universitas Indonesia, Depok 16424 (Indonesia)
3. Institut fuer Theoretische Physik, Universitaet Giessen, D-35392 Giessen (Germany)

We show how the gauge-invariance formulation given by Haberzettl is implemented in practice for photoproduction amplitudes at tree level with form factors describing composite nucleons. We demonstrate that, in contrast to Ohta{close_quote}s gauge-invariance prescription, this formalism allows electric current contributions to be multiplied by a form factor, i.e., it does not require that they be treated like bare currents. While different in detail, this nevertheless lends support to previous {ital ad hoc} approaches which multiply the Born amplitudes by an overall form factor. Numerical results for kaon photoproduction off the nucleon are given. They show that the gauge procedure by Haberzettl leads to much improved {chi}{sup 2} values compared to Ohta{close_quote}s prescription. thinsp {copyright} {ital 1998} {ital The American Physical Society}

• OSTI ID: 638833
• Journal Information: Physical Review, C, Journal Name: Physical Review, C Journal Issue: 1 Vol. 58; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
AMPLITUDES
COMPOSITE MODELS
ELECTRIC CURRENTS
FORM FACTORS
GAUGE INVARIANCE
KAONS
NUCLEONS
PHOTOPRODUCTION