Compton scattering and polarizabilities of the nucleon

TL;DR

This paper develops a dispersion relation formalism for Compton scattering off nucleons at energies up to 500 MeV, enabling extraction of nucleon polarizabilities with minimal model dependence.

Contribution

It introduces fixed-$t$ subtracted dispersion relations that directly incorporate scalar and spin polarizabilities as fit parameters, improving the analysis of experimental data.

Findings

Formalism allows model-independent extraction of polarizabilities.

Scalar polarizability difference and spin polarizability are directly fitted.

Applicable to energies up to 500 MeV.

Abstract

Fixed-$t$ subtracted dispersion relations are presented for Compton scattering off the nucleon at energies $E_\gamma \leq 500$ 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.