Abstract
In this paper we extend our systematic investigation of pion photoproduction to the case of negative pion production on neutrons. In our approach two phenomenological parameters occur in the electric and magnetic dipole amplitudesE 0+ andM 1−. These constants have been determined by a least squares fit of the total cross section data of the ABBHHM collaboration. We obtain a very good fit, also the prediction of the asymmetry ratio for polarized photons agrees with experiment at energies below and at the resonance. Serious discrepancies between theory and experiment are found for theπ −/π + ratio, moreover the relationship between the electric dipole at threshold, the Panofsky ratio and the difference ofs-waveπN-scattering lengths is fulfilled only within 20%. These discrepancies are discussed thoroughly.
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It is a pleasure to thank Prof. Dr. H.Rollnik for a critical reading of the manuscript. Discussions with Drs. K.Böckmann, E.Paul, Mr. K.Müller and Mr. E.Propach on the experimental data of the ABBHHM Collaboration are gratefully acknowledged. The numerical calculations have been performed on the IBM 7090 computer of the Institut für Instrumentelle Mathematik at Bonn.
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Schwela, D. Evaluation of the photoproduction of negative pions on neutrons in the region of the first resonance. Z. Physik 221, 158–174 (1969). https://doi.org/10.1007/BF01392140
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DOI: https://doi.org/10.1007/BF01392140