Ak. Opper et al., Measurements of the spin observables D-NN ', P, and A(y) in inelastic proton scattering from C-12 and O-16 at 198 MeV - art. no. 034614, PHYS REV C, 6303(3), 2001, pp. 4614
Precise values of the normal-component spin observables D-NN, P, and A(y) h
ave been determined at an incident proton energy of 198 MeV for the T=0 (12
.71 MeV) and T=1 (15.11 MeV) 1+ states in C-12 for momentum transfers betwe
en 80 and 250 MeV/c. and for the T=0 (17.78 and 19.81 MeV) and T=1 (18.98 M
eV) 4(-) states in O-16 for momentum transfers of 225-400 MeV/c. The data a
re compared with distorted wave impulse approximation calculations in which
a microscopic treatment of the nuclear medium has been used to obtain an e
ffective nucleon-nucleon interaction. Nuclear binding and Pauli blocking ef
fects. as well as those due to the strong scalar and vector mean held poten
tials that arise in covariant treatments of nuclear matter. are incorporate
d using a G-matrix approach. Our results suggest that while the isovector c
hannel of the effective nucleon-nucleon interaction is reasonably well unde
rstood, pronounced discrepancies between theory and experiment for the isos
calar transitions point towards problems with the relative strengths of the
spin-orbit and tensor components. For the C-12 states, these discrepancies
are more difficult to interpret due to ambiguities in the nuclear structur
e.