An issue that emerges in nuclear structure research is medium modification: do nucleons in nuclei have the same properties as free nucleons?

Theoretical predictions (backed by experimental hints) claim that some of the properties are modified. One specific prediction is for the ratio of electric and magnetic form factors, G_E/G_M, which is expected to be larger (smaller) for neutrons (protons) in nuclei than for free neutrons (protons).

I'll present the analysis of an experiment performed two years ago and a simulation for a future experiment in January, both at the Mainzer Microtron (MAMI). The ratio of the transverse and longitudinal polarization components, P_t/P_l, which is proportional to the form factor ratio for free nucleons, is measured in both experiments.

In the case of the deuteron, the proton's polarization components ratio was measured for both the bound state with different states of virtuality and for the free proton. The experiment was designed to look for possible changes in a bound proton with high momentum.

In the next experiment we'll compare the proton's polarization ratio of a proton from the different shells, and look for modification caused by the difference in the local density.