Sensitivity of quasielastic (p→,n→) spin-transfer observables to relativistic Dirac effects

Nuclear medium modifications of theNNinteraction via quasielastic(p→,p′Hillhouse1, Ventel2, Wyngaardt3 et al. 1998Phys. Rev. CSelf Cite120140View full textAdd to dashboardCite

“…As in Ref. [11], we see that for some polarization transfer observables the exchange contributions become more important at higher energies. In particular, for ( p, p ′ ) scattering, A y and D ℓ ′ s are sensitive to exchange contributions over the entire energy range.…”

“…In recent papers [10,11] we calculated better effective masses and qualitatively analyzed the sensitivity of complete sets of quasielastic ( p, p ′ ) and ( p, n) polarization transfer observables to medium effects, different forms of the πNN vertex, exchange contributions to the nucleon-nucleon (NN) amplitudes, and also spin-orbit distortions. We emphasized that the much-used SVPAT form [12] is limited in that it does not properly address the exchange behavior of the NN amplitudes in the nuclear medium, and does not properly distinguishing between pseudoscalar (PS) and pseudovector (PV) forms of the πNN vertex.…”

“…We introduce the notation D P S i ′ j (M * ) and D P V i ′ j (M * ) to refer to polarization transfer observables calculated using respectively a PS and a PV coupling for the "pion", both with the more refined effective masses M * SC from Table II in Ref. [11]. The shaded areas accentuate differences between ( p, p ′ ) and ( p, n) predictions.…”

Relativistic distorted-wave analysis of quasielastic proton-nucleus scattering

“…Introducing distorted waves for the projectile and ejectile in quasielastic proton-nucleus scattering represents a significant improvement over previous work [2][3][4][5][6][7]25] which utilized the plane-wave impulse approximation. A choice must be made between a full partial-wave expansion or some approximation which retains the essentials of distortion effects.…”

“…[1], Hillhouse et al studied various aspects of the model in a series of papers [2][3][4][5][6][7], namely, (i) more refined self-consistent calculations of the projectile and ejectile effective masses, (ii) sensitivities of the complete set of spin observables to different five-term parametrizations of the NN interaction, (iii) new meson-exchange parameters for the relativistic NN amplitudes, (iv) medium modifications of the NN interaction and the effect on ( p, p ) and ( p, n) complete sets of spin observables, and (v) the replacement of the ambiguous five-term parametrization ofF by a general Lorentz-invariant representation.…”