Institut für Kernphysik, Johannes Gutenberg Universit?t, D-55099 Mainz, Germany, DE
Abstract:
Differential cross-sections for Compton scattering from the proton have been measured at the MAMI tagged photon facility using the TAPS setup. The data cover an angular range of θlabγ = 59°-155° and photon energies ranging from 55 MeV to 165 MeV. Our results are in good agreement with those from previous experiments, but yield higher precision. Using dispersion relations the proton polarizabilities have been determined to be = [11.9±0.5stat.±1.3syst.±0.3mod.] . 10-4fm3 and = [1.2±0.7stat.±0.3syst.±0.4mod.)] . 10-4fm3. These results confirm the Baldin sum rule which was re-evaluated to be + = [13.8±0.4] . 10-4fm3. We can also conclude that there is no significant additional asymptotic contribution to the backward spin polarizability γπ beyond the t-channel π0-exchange. Received: 9 January 2001 / Accepted: 13 February 2001