Nucleon helicity in pion photoproduction
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 are 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 nonconserving amplitudes.
- Publication:
-
Physical Review C
- Pub Date:
- December 1995
- DOI:
- 10.1103/PhysRevC.52.3499
- arXiv:
- arXiv:hep-ph/9509289
- Bibcode:
- 1995PhRvC..52.3499J
- Keywords:
-
- 12.38.Qk;
- 24.85.+p;
- 25.10.+s;
- 25.20.Dc;
- Experimental tests;
- Quarks gluons and QCD in nuclei and nuclear processes;
- Nuclear reactions involving few-nucleon systems;
- Photon absorption and scattering;
- High Energy Physics - Phenomenology
- E-Print:
- plain tex, 6 pages, 8 figures