Differential cross sections of proton compton scattering in the resonance region

Abstract

Differential cross sections of proton Compton scattering have been measured in the energy range between 375 MeV and 1150 MeV in steps of 25 MeV at c.m. angles of 130°, 100° and 70°. The recoil proton was detected with a magnetic spectrometer. In coincidence with the proton, the scattered photon was detected with a lead-glass Čerenkov counter of the total absorption type. Theoretical calculations based on an isobar model with two components, that is, the resonance plus the background, were practiced. The photon couplings of the second resonance region were determined from the proton Compton data for the firs time. The results were that the helicity 1 2 photon couplings of P 11(1470) and S 11(1535), and the helicity 3 2 photon coupling of D 13(1520) were consistent with those determined from the single-pion photoproduction data; however, the helicity 1 2 photon coupling of D 13(1520) required a somewhat larger value than that from the single-pion photoproduction data.