Analysis of data on low-energy gamma-p scattering and determination of proton polarizabilities

Abstract

An analysis of all experimental data of 50's - 90's on elastic gamma-p scattering at photon energies below 150 MeV (10 experimental works) is performed in order to determine the electric (alpha_p) and magnetic (beta_p) polarizabilities of the proton. A fit of these data with the two free parameters, alpha_p and beta_p, embedded into a theoretical cross section obtained on the basis of finite-energy s-channel dispersion relations gives the following world-average values of the proton polarizabilities (in units of 10^{-4} fm^3): alpha_p = 11.7 +- 0.8 (stat+sys) +- 0.7 (model), beta_p = 2.3 +- 0.9 (stat+sys) +- 0.7 (model), where the first error takes into account statistical and systematic errors of the experimental cross sections and the second error does model uncertainties in the theoretical cross section.