{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"e6a213d782ef1a95fdc361786d0657c8674c7d1c68b4a3d71ac81087fc41ec81","created":"2026-10-03T07:18:07Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"fa91cda4dd7086d889f10236f59797da640fb7302595eb3c50818c7ed835d053","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":"1","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 $R_s = \\sigma_{\\mathrm{exp}}/\\sigma_{\\mathrm{th}}$, 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.","problem_ref":null,"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":"2e3c9bbdd2ce5849bb4ba420a815301d70db5fbf0341e1a0ed3d81994b4e4b35"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"4e32ebf526696e88abdf82992d6a92a49256bcf3e450afae8b054d6579a6af44","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"d2527869e800c97fad9dcfd15d8e543b7c6d4d57febec9d5a36b377469d4fe77","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"IECX2ASWF3Hy-y-jCSc8PmVDc6wTOTD9jRhvcHQinFBk2TxcN-nkZDWrGyeuDCJIEj_Z_V_4pnlrHC1JnlGFAQ"},"schema":"pubphys.envelope/1"},"record_hash":"4e32ebf526696e88abdf82992d6a92a49256bcf3e450afae8b054d6579a6af44","leaf_index":1734}