Nuclear Density Dependence of In-Medium Polarization

TL;DR

This paper demonstrates how polarization transfer measurements in electron scattering can constrain the in-medium electric to magnetic form factor ratio by exploiting the density sensitivity of proton knockout from different nuclear shells.

Contribution

It introduces a method to use polarization transfer data to probe the nuclear density dependence of in-medium nucleon form factors, highlighting shell-specific density effects.

Findings

Effective nuclear density for s-shell knockout is about twice that for p-shell in carbon-12.

Predicted in-medium form factor modifications are around 5% in polarization observables.

Proposes measurable polarization transfer differences linked to nuclear density variations.

Abstract

It is shown that polarization transfer measurements $(\vec{e},e'\vec{p})$ on a specific target nucleus can provide constraints on the ratio of the in-medium electric to magnetic form factor. Thereby one exploits the fact that proton knockout from single-particle levels exhibit a specific sensitivity to the effective nuclear density. It is shown that in $^{12}$C the effective nuclear density for $s$-shell knockout is about twice as high as for $p$-shell knockout. With current model predictions for the in-medium form factors, one obtains measurable modifications of the order of 5% in the ratios of the double polarization observables between those single-particle levels.