Dispersion relation formalism for virtual Compton scattering off the proton

Abstract

We present in detail a dispersion relation formalism for virtual Compton scattering (VCS) off the proton from threshold into the $\hat{I}”(1232)$-resonance region. Such a formalism can be used as a tool to extract the generalized polarizabilities of the proton from both unpolarized and polarized VCS observables over a larger energy range. We present calculations for existing and forthcoming VCS experiments and demonstrate that the VCS observables in the energy region between pion production threshold and the $\hat{I}”(1232)$-resonance show an enhanced sensitivity to the generalized polarizabilities.

51 pages, 15 figures