Electromagnetic interference in high energy polarization

The polarization of high energy protons may be determined from an asymmetry measurement in the hadron-electromagnetic interference region of proton-proton elastic scattering. This paper examines a contribution to the expected 5% asymmetry from the single helicity-flip hadronic amplitude. An expression in terms of polarization and spin rotation parameters allows the size and error of this contribution to be estimated over a range of moments from 3.8 to 45 Gev/c. Indications are that the asymmetry approaches the expected asymptotic value with weak energy dependence approx. = 1/(square root)sigma(tot). Nuclear targets display somewhat lower asymmetries than those of the proton, but they are comparable. 13 references