Isospin-asymmetry dependence of single-nucleon removal strength · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title
Isospin-asymmetry dependence of single-nucleon removal strength
Plain
When one nucleon is knocked out of a nucleus, experiments find fewer nucleons in each orbit than the simple shell model predicts, a reduction called quenching. In knockout reactions with fast radioactive beams the reduction grows strongly for the more tightly bound kind of nucleon in very neutron- or proton-rich nuclei, while other reaction types show little such trend.
Precise · changed · core
Revision 1: Define $R_s = \sigma_{\mathrm{exp}}/\sigma_{\mathrm{th}}$, the ratio of measured to predicted (shell model times reaction theory) single-nucleon removal cross sections, and $\Delta S$, the separation energy of the removed nucleon minus that of the other species. Intermediate-energy knockout on light targets shows $R_s$ falling from roughly 0.9 to roughly 0.3 as $\Delta S$ goes from about $-20$ to $+20\,\mathrm{MeV}$, whereas transfer, $(p, 2p)$, $(p, pn)$ and $(e, e' p)$ data show weak or no dependence (Aumann et al., Prog. Part. Nucl. Phys. 118, 103847, 2021). Answer: whether the trend reflects nuclear correlations or reaction-model approximations (eikonal and sudden treatment, core excitation), with an ab initio prediction of $R_s(\Delta S)$ consistent across reaction types.
Revision 2: Define $R_s = \sigma_{\exp}/\sigma_{\mathrm{th}}$, the ratio of measured to predicted (shell model times reaction theory) single-nucleon removal cross sections, and $\Delta S$, the separation energy of the removed nucleon minus that of the other species. Intermediate-energy knockout on light targets shows $R_s$ falling from roughly 0.9 to roughly 0.3 as $\Delta S$ goes from about $-20$ to $+20\,\mathrm{MeV}$, whereas transfer, $(p, 2p)$, $(p, pn)$ and $(e, e' p)$ data show weak or no dependence (Aumann et al., Prog. Part. Nucl. Phys. 118, 103847, 2021). Answer: whether the trend reflects nuclear correlations or reaction-model approximations (eikonal and sudden treatment, core excitation), with an ab initio prediction of $R_s(\Delta S)$ consistent across reaction types.
Settled by
Removal of the same deeply bound nucleon from identical rare-isotope beams by knockout and by quasi-free scattering, analyzed with ab initio overlap functions in a common reaction framework.
Kind
phenomenon
Answer type
identification
References
(empty)
Literature status
contested
Status note
The 2021 community review (Aumann et al.) left the dependence on reaction method unresolved, and it remained debated as of 2026.
Posed since
(empty)

Decisions