{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"7c4a60e153cd03cc40384fb5bf0375f2310237af3e4e2d0cda1dabef189c8088","created":"2026-10-03T07:18:08Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"160e65eff651d6dbe54ec7d4e516e8a211414b1566a340e6c4234bdb0bc2ef59","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"nuc.r-process-nuclear.rare-earth-peak","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"plain":"The solar system has a small extra bump in the abundances of rare-earth elements near mass 160. Whether it comes from nuclear deformation (nuclei becoming non-spherical) late in the r-process or from fission fragments is not known.","posed_since":"1997","precise":"Determine whether the r-process rare-earth peak at $A$ about 160 forms by trapping of material at deformed nuclei near $N$ about 104 during freeze-out (Surman et al., 1997) or by deposition of fission fragments, and identify the nuclear properties (masses and half-lives for $Z = 60\\ \\text{to}\\ 66, N = 100\\ \\text{to}\\ 110$) that control it. Answer: the mechanism and the specific nuclei whose properties set the peak.","problem_ref":null,"references":"","settled_by":"Mass and half-life measurements across the neutron-rich lanthanides at FRIB and CARIBU, fed into network calculations for merger and collapsar conditions.","status_note":"Mass measurements of neutron-rich lanthanides at Argonne since about 2016 began to test the deformation mechanism without deciding between the two pictures as of 2026.","title":"Origin of the rare-earth abundance peak","topic_ref":"008542e5fb6a342c0c764df9c1f7e628886ae3efa8048a1b79e833430d025799"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"112b7a8571a4d1e9ef42569f1210fe8832903e85d572fa0af3d3cce2e03c5432","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"c2584a7ecd4276d4bdfc762b319b2498f973d62a9773b72788421812851e2692","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"9NOPYZOIh-uGWSKM-wBsD8kpVDsXUMOFLFxEpPXj-pOWtPi4VcT-SxCO12iuL6QhSl4wGDncBpZs1baXClqGBA"},"schema":"pubphys.envelope/1"},"record_hash":"112b7a8571a4d1e9ef42569f1210fe8832903e85d572fa0af3d3cce2e03c5432","leaf_index":1810}