Speaker
Description
A comparison between polarization-transfer to a bound proton in quasi-free kinematics by the $A(\vec e,e'\vec p)$ knockout reaction
and that in elastic scattering off a free proton can provide information on the characteristics of the bound proton. In elastic scattering, the ratio of the transverse ($P_x$)
to longitudinal ($P_z$) polarization-transfer components is proportional to the electromagnetic form factor ratio $G_E/G_M$. This provides a direct measurement of the form factor (FF) ratio and eliminates many systematic uncertainties. Similar measurements in quasi-elastic scattering off bound protons have been performed at the Mainz Microtron (MAMI) using $^2$H and $^{12}$C targets, with $Q^2$ up to 0.65 GeV$^2/c^2$. These measurements are compared to the free-proton scattering, as well to realistic calculations that include nuclear effects such as final state interactions (FSI), in order to search for nuclear-medium modifications of the nucleon. Comparison of the individual components $P_x$ and $P_z$ to the calculated predictions are used to further test the validity of the calculated polarizations.
This talk will explain the setup of the experiment, the methods used to derive $P_x$, $P_z$ and their ratio, as well as the calculated predictions that they are compared to. It will also present the polarization observables, as well as the ratio of the observables to those of elastic scattering off a free moving proton.
| Graduate Student | No |
|---|---|
| Early Consideration | No |
