Compton scattering and polarizabilities of the nucleon

Abstract

Fixed-$t$ subtracted dispersion relations are presented for Compton scattering off the nucleon at energies $E_{\gamma }\le 500$ MeV, as a formalism to extract the nucleon polarizabilities from the data with a minimum of model dependence. The scalar polarizabilities difference $\alpha -\beta$ and the backward spin polarizability ${\gamma }_{\pi }$ enter directly as fit parameters in this formalism.

Comments: 2 pages, 1 figure Talk given at the Erice School on Nuclear Physics, Erice, Sicily, Italy September 17-25, 1999