Polarization in the quasielastic scattering of 1-GeV/c protons on light nuclei

Polarization measurements in the A(p, 2p)B reactions on Li-6, Li-7, and Si- 28 nuclei at a proton-beam energy of 1 GeV were performed in a kinematicall y complete experiment. By using a two-arm magnetic spectrometer, two second ary protons were recorded in coincidence at asymmetric scattering angles of theta(1) = 15 degrees-26 degrees and theta(2) = 58.6 degrees for residual- nucleus momenta in the range K-B = 0-150 MeV/c. Either arm of the spectrome ter was equipped with polarimeters based on proportional chambers. The data coming from this experiment are analyzed within the distorted-wave impulse approximation. It is shown that the polarization of recoil protons formed at angle theta(2) in the interaction featuring a proton from the P shell of the Li-7 nucleus can be described under the assumption of an effective int ranuclear-proton polarization by using the single-particle shell-model wave function of the nucleus. Our data on the polarizations of the two protons from the reaction (p, 2p) on a Si-28 nucleus also suggest the effective pol arization of the protons in the D shell of the Si-28 nucleus. It is found t hat, for high recoil-nucleus momenta of K-B greater than or equal to 90 MeV /c, the effective polarization of the protons in the P shell of the Li-6 nu cleus-this polarization was discovered in studying the polarization of reco il protons in the reaction Li-6(p, 2p)He-5-cannot be described within the s hell model assuming LS coupling. As might have been expected, the polarizat ion of recoil protons knocked out from the S shells of the Li-6 and Li-7 nu clei comply well with the predictions obtained in the impulse approximation with allowance for the depolarization effect alone. (C) 2000 MAIK "Nauka/l nterperiodica".