6533b850fe1ef96bd12a82b0

RESEARCH PRODUCT

Low-energy Compton scattering and the polarizabilities of the proton

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description

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 θlab γ = 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.] . 10-4 fm 3 and = [1.2±0.7stat.±0.3syst.±0.4mod.)] . 10-4 fm 3. These results confirm the Baldin sum rule which was re-evaluated to be + = [13.8±0.4] . 10-4 fm 3. We can also conclude that there is no significant additional asymptotic contribution to the backward spin polarizability γπ beyond the t-channel π0-exchange.