{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"2c716e28c45913e8d68fae602b50c07901bde787724336d219a7e965409cb766","created":"2026-10-03T07:18:05Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"dbd82837dc42b5914543300c6f5be9bf1ee8b2994cd0a62fe559cd53d0311f89","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"classification","assisted_by":[],"external_id":"hep.neutrino-mass.mass-ordering","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"We know the mass differences between the three neutrinos but not whether the odd one out is heaviest (normal ordering) or lightest (inverted ordering).","posed_since":"","precise":"Determine the sign of $\\Delta m^2_{31}$ ($\\left|\\Delta m^2_{31}\\right| \\sim 2.5e-3\\,\\mathrm{eV}^2$) at $\\ge 3\\,\\sigma$ from reactor oscillation spectra (JUNO), matter effects in long-baseline accelerator (DUNE, Hyper-K) and atmospheric data. Answer: normal or inverted.","problem_ref":null,"references":"","settled_by":"JUNO reactor spectral data over about 6 years combined with DUNE and atmospheric experiments.","status_note":"JUNO 207-day data combined with long-baseline accelerator $\\Delta m^{2}_{31}$ constraints (arXiv:2609.37895, September 2026) favor normal ordering at one-sided $\\ge 2.1\\sigma$ for all $\\delta_{\\mathrm{CP}}$ (Bayes factor 10.18); global fits (NuFit-6.0, 2024) also lean normal; the 2025 NOvA plus T2K joint fit prefers neither.","title":"Is the neutrino mass ordering normal or inverted?","topic_ref":"bf623edd63337963e5d02d169573ea3befbc30edcb8ee813200a0e5d35d5421d"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"39015d3bd3dc418826d0f250280ff88e9ffaca603aadb4336b3c7f141052a6ce","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"8fdc053cc190270b01effeebf5ea57881061c5f5c9f066acd48f897402b4f310","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"jNyPC83VbZ-hlfcGniwbBPCk2sz_gNpMuLn9aJt7820ZKqjf6ipMrGlYusc1YlKYfS7nzJpXctnY3ayCsfbbAw"},"schema":"pubphys.envelope/1"},"record_hash":"39015d3bd3dc418826d0f250280ff88e9ffaca603aadb4336b3c7f141052a6ce","leaf_index":1572}