It is shown that polarization transfer measurements $(\vec{e},e^{\prime }\vec{p})$ 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.

• Received 18 December 2012

DOI:https://doi.org/10.1103/PhysRevC.87.028202