{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"3413e3ee93118e5487773130a6d8e4ec750089a63d5e68ee4c075bc46817d009","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b","e26a954814709de6a21c0c6742078135befff4d202e9194d2771193699e31948"],"salt":"b9c8e62d947db32262aa023ead1792e91ac42dccf5c5cbc954f534e18b69bff6","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":["ai:gpt-5.5"],"external_id":"hep.grand-unification.proton-lifetime","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"Grand unified theories predict a proton can decay into a positron and a neutral pion. Huge water detectors watch for this rare event.","posed_since":"1974","precise":"Measure or bound $\\tau(p \\to e+ \\pi0)/B$, currently $> 2.4 \\times 10^{34}\\,\\mathrm{yr}$ (Super-Kamiokande, 2020, 90 percent CL). Non-supersymmetric $\\mathrm{SO}(10)$ models with intermediate scales typically predict $10^{34}\\text{ to }10^{36}\\,\\mathrm{yr}$. An answer is a detection or a limit near $10^{35}\\,\\mathrm{yr}$.","problem_ref":"e26a954814709de6a21c0c6742078135befff4d202e9194d2771193699e31948","references":"","settled_by":"Hyper-Kamiokande exposure of about 1 to 2 Mt-yr reaching $\\sim 10^{35}\\,\\mathrm{yr}$ sensitivity.","status_note":"Hyper-Kamiokande construction is under way, with data expected late in the 2020s.","title":"Is the proton lifetime to $e+ \\pi0$ below $10^{35}\\,\\mathrm{years}$?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"858f03e26dd2e9b9c1dad42588a61ad097a5db6c57a3e64400af6d70d8137d1d","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"ee428795852a4ef60ab774bc85a4fa4421b3df0de1b4bfbdc36847e554722ac5","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"0ReNmTG6RcDFU8NoNWs5TmaWuQxYHOp8NPnwvxBP54biFKhClBs-aPLkyJ4md9-aFsn6Wi4e1-eBHdk14O_hBA"},"schema":"pubphys.envelope/1"},"record_hash":"858f03e26dd2e9b9c1dad42588a61ad097a5db6c57a3e64400af6d70d8137d1d","leaf_index":3350}