Year: 2015
Type: article
Abstract: We derive two relations involving spin polarizabilities of a spin-$1/2$ particle and consider their empirical implications for the proton. Using the empirical values of the proton anomalous magnetic moment, electric and magnetic charge radii, moments of the spin structure functions ${g}_{1}$, ${g}_{2}$, and of two spin polarizabilities, the present relations constrain the low-momentum behavior of generalized polarizabilities appearing in virtual Compton scattering. In the case of the proton, the dispersive model evaluations of the spin and generalized polarizabilities appear to be consistent with these relations. The ongoing measurements of different electromagnetic observables at the MAMI, Jefferson Lab, and $\mathrm{HI}\ensuremath{\gamma}\mathrm{S}$ facilities may be able to put these relations to a test, or use them to unravel the low-energy spin structure of the nucleon.
Authors: Vladimir Pascalutsa, Marc Vanderhaeghen
Institution: Johannes Gutenberg University Mainz
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: Deutsche Forschungsgemeinschaft
OpenAlex ID: W2009769455