{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"6873848cb823e0e3e6f0c8299a9213ef323e313f1db4ed12a8cb4b647b4d9e5f","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["4e32ebf526696e88abdf82992d6a92a49256bcf3e450afae8b054d6579a6af44","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"1922c0c6d97130af8c979156420ee221d3824c49a7d06e4e2622f149bb2faa70","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"nuc.ab-initio-nuclei.spectroscopic-factor-quenching","kind":"phenomenon","literature_status":"contested","n":"2","parents":[],"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.","posed_since":"","precise":"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.","problem_ref":"4e32ebf526696e88abdf82992d6a92a49256bcf3e450afae8b054d6579a6af44","references":"","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.","status_note":"The 2021 community review (Aumann et al.) left the dependence on reaction method unresolved, and it remained debated as of 2026.","title":"Isospin-asymmetry dependence of single-nucleon removal strength","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"e8f560be08e362dd99a15f8ce92eebb3756788a6feee05b4c204df9c4a843b40","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"578f2a54bb3945557d2f4443b973c812575f8c0c0b695af9f59a71982adcd26a","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"Xt9KfPVzbI9ogroGfIcxLjYbMUIQbFdVQ-rXILY4sReDBKc_a3pDvcP_9EMStt_ACnbgooQm9YNzzMKqpBDzDQ"},"schema":"pubphys.envelope/1"},"record_hash":"e8f560be08e362dd99a15f8ce92eebb3756788a6feee05b4c204df9c4a843b40","leaf_index":3488}