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arXiv · hep-ph/9509289

Nucleon Helicity in Pion Photoproduction

D. A. Jenkins·I. I. Strakovsky
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Abstract

Pion-photoproduction data is examined to check for the nucleon-helicity conservation predicted by asymptotic QCD. The differential cross section shows agreement with constituent-counting rules, and polarization data is not in disagreement with conservation of nucleon helicity. However large uncertainties in the polarization measurements do not allow a conclusive statement. The helicity amplitudes from a partial-wave analysis are also examined for helicity conservation. While the amplitudes become small as $s$ increases, the $s$ dependence of the helicity-conserving amplitudes is similar to the dependence of the non-conserving amplitudes.

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D. A. Jenkins, I. I. Strakovsky. 1995-09-13. Nucleon Helicity in Pion Photoproduction. https://doi.org/10.1103/physrevc.52.3499

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