Spin-dipole strengths and tensor correlation effects for ${}^{208}{\rm Pb}(p,n)$ at 295 MeV

TL;DR

This study analyzes the spin-dipole strength distributions in lead-208 using multipole decomposition and compares experimental data with RPA calculations, highlighting the influence of tensor correlations on resonance properties.

Contribution

The paper provides a detailed separation of spin-dipole strengths and investigates tensor correlation effects not included in standard RPA models.

Findings

RPA reproduces total SD strength well but shows discrepancies in separated strengths.

Resonance centroids for 1^- and 2^- are slightly shifted from theoretical predictions.

Tensor correlations may explain observed softening and hardening effects.

Abstract

We performed the multipole decomposition analysis (MDA) for the ${}^{208}{\rm Pb}(p,n)$ data in order to obtain the spin-dipole (SD) strengths separated into each $\Delta J^{\pi}$ contribution $dB({\rm SD}_{\Delta J^{\pi}};\omega)/d\omega$. The random phase approximation (RPA calculations reproduce the total SD strength reasonably well, whereas some discrepancies are found for separated SD strength. The centroids of the resonances are slightly lower and higher than the theoretical predictions for $1^-$ and $2^-$, respectively. These softening and hardening effects observed in $1^-$ and $2^-$ distributions would be due to the tensor correlation effects not included in the present RPA calculations.