New sum rule for the nuclear magnetic polarizability

TL;DR

This paper introduces a new sum rule linking nuclear magnetic polarizability to virtual photon absorption, extending existing photonuclear sum rules to include virtual photons and providing a tool for nuclear structure analysis.

Contribution

It derives a novel sum rule for nuclear magnetic polarizability involving virtual photons, expanding the theoretical framework of photonuclear sum rules.

Findings

Sum rule verified for the deuteron with available data

Discussion on applications and connections with other sum rules

Potential use in nuclear structure studies

Abstract

I extend the well-known photonuclear sum rule that relates the strength of the photoexcitation of the giant dipole resonance in a nucleus to the number of elementary scatterers-nucleons to the case of virtual photons. The new sum rule relates the size of the magnetic polarizability of a nucleus to the slope of the transverse virtual photoabsorption cross section integrated over the energy in the nuclear range. I check this sum rule for the deuteron where necessary data is available, discuss possible applications and connection with other sum rules postulated in the literature.