{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"b1cf693cbe89b80c31f0b47274bbe9f9e07dbdd2b455c9e34e5e7b474e94e3a1","created":"2026-10-03T07:18:07Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011","84ce1c7bc46a6b9febd203bba7fde4af888b1a1871f94c4879fdfe4060d3970b"],"salt":"5e04038f28b045b3ca62a9c5c3c3020ab0a7b08c92aa9b7d38d6542874776598","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"nuc.precision-anomalies.x17-nuclear-explanation","kind":"well-posed","literature_status":"open","n":"1","parents":[{"note":"","parent_revision":"84ce1c7bc46a6b9febd203bba7fde4af888b1a1871f94c4879fdfe4060d3970b","relation":"special_case"}],"plain":"The extra pairs might come from ordinary nuclear effects, such as interference between different ways an excited nucleus emits a pair, or from the detector response. A complete calculation is needed to decide.","posed_since":"","precise":"Compute internal pair creation e+ e- angular correlations for the $8\\mathrm{Be}$ $18.15\\,\\mathrm{MeV}$ ($M1$), $4\\mathrm{He}$ $20.21\\,\\mathrm{MeV}$ ($E0$ and $M0$) and $12\\mathrm{C}$ $17.23\\,\\mathrm{MeV}$ transitions including interference of $E0$, $E1$ and $M1$ multipoles, direct-capture components and ab initio transition form factors, and determine whether they produce peaks near 140 degrees ($8\\mathrm{Be}$) or 115 degrees ($4\\mathrm{He}$) of the observed size. Answer: yes or no, with the predicted angular distributions.","problem_ref":null,"references":"","settled_by":"Full-multipole calculations with ab initio form factors compared bin by bin with ATOMKI and MEG II angular distributions after detector simulation.","status_note":"","title":"Can standard nuclear physics produce the ATOMKI angular excess?","topic_ref":"68930a0e96cfb6023c51ad2da3d1ea500482dc0e5e690cd3ea4398d0ad9ecbec"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"bd1e72c14b9459dd91dbc26bfefad7ffc8f57c795d53c3f14d24eabda83ce886","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"b9b78e3e185efc17bb28c889e4716b688fcfb66ada0694f162114c429095c983","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"K6Ma_WrrbBbQe7KOtbwlGo6Afi1uw_HsJ4EHs_sUNvAIDOim8dH6v9t6lWDVN1Qih4u6AWE8ZR6loajKdM9xAQ"},"schema":"pubphys.envelope/1"},"record_hash":"bd1e72c14b9459dd91dbc26bfefad7ffc8f57c795d53c3f14d24eabda83ce886","leaf_index":1790}