{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"429db5a2dff6828e56e50e5eabf52c527e1b3e13551d210cd05010a9b73d4998","created":"2026-10-03T07:18:07Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["2088d5da82ff57b84ab6c40e494e14780fbb907ecb8a72c339a9b1d4f5747616","5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"ebc868c6e61c5f95da0bd4f8fa41269cade90ad8b6b16d2ccd5c9a3a2a5c3bc7","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"nuc.precision-anomalies.dark-decay-channel","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[{"note":"","parent_revision":"2088d5da82ff57b84ab6c40e494e14780fbb907ecb8a72c339a9b1d4f5747616","relation":"special_case"}],"plain":"If about 1 percent of neutrons decayed into invisible particles, bottles would see neutrons vanish faster than beams see protons appear, explaining the gap. Searches have found no such decay so far.","posed_since":"2018","precise":"Test whether the neutron has an exotic branch $n \\to \\chi + \\text{anything}$ (Fornal and Grinstein, PRL 120, 191801, 2018) with branching ratio about 1 percent and $937.9\\,\\mathrm{MeV} < m_{\\chi} < 938.8\\,\\mathrm{MeV}$, as needed to explain the beam-bottle gap. Answer: yes or no; if no, a limit on any invisible branch below 0.1 percent from direct searches and from consistency of $\\tau_{n}$ with $\\lambda = g_{A}/g_{V}$ and $V_{ud}$.","problem_ref":null,"references":"","settled_by":"Agreement of a sub-second beam lifetime with the bottle value, or direct detection of the invisible branch.","status_note":"Direct searches (2018 onward) and neutron-star mass limits exclude the simplest versions, and the Standard Model relation with $\\lambda$ from PERKEO III (2019) favors the bottle value, as of 2026.","title":"Is there a roughly one percent exotic neutron decay?","topic_ref":"68930a0e96cfb6023c51ad2da3d1ea500482dc0e5e690cd3ea4398d0ad9ecbec"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"c8d6f9d28782ae82dd98542dacee3c13b3ce46a1f7ed9c00578319300dad1aa1","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"4e4c4e9e54b9bcdd863bcb1fbc19f55fd5c30dc5faccabb7bbee67a8342e3a9b","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"iSSjo5oOIclZKsGCod2TrV6TNsE3nAklb78ZvHpD2XslpW2fOsFtA4W-8w5YfVd_R6I48dHhF7lfGSTtfFJwCQ"},"schema":"pubphys.envelope/1"},"record_hash":"c8d6f9d28782ae82dd98542dacee3c13b3ce46a1f7ed9c00578319300dad1aa1","leaf_index":1785}