{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"cf3c1e190ecf14528d0390bd9a317d6bdb7a322484f8c04b9fe7a26362192979","created":"2026-10-03T07:18:05Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"30d69d21ae772d5bba94dd534c3858937bafc176985c3b8941857220a7873964","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"hep.grand-unification.neutron-antineutron","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"Some theories allow a neutron to turn into its own antiparticle, changing baryon number by two. This would not show up in proton decay searches.","posed_since":"1970","precise":"Search for $\\Delta B = 2$ neutron-antineutron oscillations with free-neutron oscillation time $\\tau_{\\mathrm{nnbar}} > 8.6e7\\,\\mathrm{s}$ (ILL, 1994) and bound-neutron limits converting to $\\sim 4.7e8\\,\\mathrm{s}$ (Super-Kamiokande, 2021). An answer is a detection or a free-neutron limit improved by 1 to 3 orders of magnitude.","problem_ref":null,"references":"","settled_by":"The proposed NNBAR experiment at the European Spallation Source and bound-neutron searches in DUNE and Hyper-Kamiokande.","status_note":"","title":"Do neutrons oscillate into antineutrons?","topic_ref":"4ab26fd00d33deeca52b12d9aa2bb5b76a58cde8ecf899d995d016d99ca5ba55"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"c33bc4fa1e7ac15424162a61d3c3048525dc366852aac44e27e7317f73b058ae","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"771b1e45d13dff7c1e7bb7dec2cbe22a3d610325ad4227ffff9f58269bf0dfd1","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"hwwdoDci7C7Ij59Ds83-bF3cPUP-g-U44elAmClBrtcq9J_VhRgetIJ-LKAprskcpS24gl4rk9xci4P3uCXLCA"},"schema":"pubphys.envelope/1"},"record_hash":"c33bc4fa1e7ac15424162a61d3c3048525dc366852aac44e27e7317f73b058ae","leaf_index":1545}