Medium effects on spin observables of proton knockout reactions

Abstract

Medium modifications of the properties of bound nucleons and mesons are investigated by means of intermediate energy quasifree proton knockout reactions with polarized incident protons, by comparison of quantities which are insensitive against wave distortions. The sensitivity of the spin observables of the quasifree proton-proton cross section to modifications of the nucleon and meson properties is studied using the Bonn one-boson exchange model of the nucleon-nucleon interaction. A method proposed to extract the pp analyzing power in medium from the (p, 2p) asymmetries indicates a reduction of this quantity compared to its free space value. This reduction is linked to modifications of masses and coupling constants of the nucleons and mesons in the nucleus. The implications of these modifications for another spin observable to be measured in the future are

Pauli blocking and medium effects in nucleon knockout reactions

“…[29][30][31]). The medium effects were shown to play an important role on the total cross sections and on the spin observables.…”

Relativistic predictions of spin observables for exclusive proton knockout reactions

“…In particular, we invoke the scaling relations proposed by Brown and Rho [3], and also applied by Krein et al [18] to (p, 2p) reactions, namely…”

Quasifree (p,2p) and (p,pn)

“…Even in the energy region of several hundred MeV, where the NN cross section shows its minimum and the reaction mechanism is expected to be simplest, multistep processes are not negligible in general [23][24][25][26][27]35].…”