Measurements of the induced polarization in the quasi-elastic A(e,e′p→)

Measurements of the electron-helicity asymmetry in the quasi-elastic A(e→,e′p)<

“…proton-polarimeter and spinprecession cuts). This results in much higher event tally compared to those measurements [11][12][13][14][15][16][17].…”

“…Enhancements of the asymmetries measured for p-shell protons around p miss ≈ 0 in 12 C have been observed also in the transferred polarization in the ( e, e p) [14,15] as well as in the induced asymmetry in the (e, e p) reactions [17]. The polarization-transfer double ratio (P x /P z ) 12 Cp /(P x /P z )…”

“…Following [11][12][13]17], we required the missing mass of the 2 H( e, e p ) reaction to be consistent with the mass of a neutron. For the 12 C sample, we distinguish between protons knocked out from the s and p shells, following [3,[15][16][17]25], by using cuts on the missing energy of the reaction, E miss , defined as [25]:…”

“…where ω = k 0 − k 0 is the energy transfer, T p is the measured kinetic energy of the outgoing proton, and T11 B is the calculated kinetic energy of the recoiling residual system, assuming it is 11 B in the ground state. For the s-shell sample, we used the cut 30 < E miss < 60 MeV, while for the p-shell sample, we used 15 < E miss < 25 MeV [3,[14][15][16][17]25].…”

“…In search of deviations of the form factors of a bound proton from the free proton ones these measurements have been compared to calculations which are sensitive to this ratio. The treatment of the reaction mechanism and the nuclear effects in these calculations must be tested against experiments which are less sensitive to the nucleon structure, such as the induced polarization in the knocked-out proton by the A(e, e p) reaction [17] or the electron-helicity asymmetry through the A( e, e p) reaction.…”