4He(p,2p) Reactions for Studying In-Medium NN Interactions

A_y has been measured for the ⁴He(p,2p) reaction at 392 MeV. The measured value of A_y at 0 MeV/c is 30% lower than the the value of A_y from calculation, but the effect of central high density of the ⁴He nucleus is not observed clearly as the reaction might take place at the outside of the nucleus. The cross section has also been measured under three kinematic conditions, the results agreeing to within 10% FWHM.