Unnatural-parity (p,p') reactions in a factorized impulse-approximation model for polarization transfer and spin responses

TL;DR

This paper investigates polarization transfer observables in (p,p') reactions at intermediate energies, comparing experimental data with theoretical models to understand spin responses and the role of exchange contributions.

Contribution

It introduces a systematic analysis of polarization-transfer observables in unnatural-parity states using both zero-range and finite-range calculations, highlighting the differentiation of spin-orbit interactions.

Findings

Experimental and calculated $D_K$ values show good agreement.

Exchange contributions significantly affect the polarization observables.

Spin-observable combinations effectively distinguish isoscalar and isovector interactions.

Abstract

Linear combinations $D_K$ of the complete polarization-transfer observables, Dij, in the (p,p') reaction at intermediate energies are demonstrated. A comparison between systematized measured and calculated values of the combinations $D_K$ for the $1^+$ (T = 0 and T = 1) levels in $^{12}$C, for the $4^-$ (T = 0 and T = 1) states in $^{16}$O, and for the $6^-$ (T = 0 and T = 1) levels in $^{28}$Si are reported. Particularities in angular distributions of transverse- and longitudinal-spin-transfer probabilities, $D_K$, for the T = 0 and T = 1 unnatural-parity states in the indicated nuclei are discussed. The spin-observable combinations Dls allowed to differentiate reliably the strength of the isoscalar and isovector spin-orbit interactions. The comparison of experimental $D_K$ and calculated $D_K$ with the use of zero-range treatment (LEA code) and exact finite-range calculations (DWBA-91 program) made it possible to identify the role of exchange contributions.