{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"5c7fb95c9c0f96ffad6d251f7b7d55606795e62cfdd3750b44191c45508b589e","created":"2026-10-03T07:18:05Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"9ba1ef967a7d8a1c4c6b5f82377b10b876f7aecf19d40e2e395438aa7e82f17e","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"hep.flavor-puzzle.charged-lfv","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"The SM forbids a muon from turning into an electron without neutrinos, except at hopelessly tiny rates. Seeing it would prove new physics acting on flavor.","posed_since":"","precise":"Measure or bound the coherent conversion rate $R_{\\mathrm{mue}} = \\Gamma(\\mu- N \\to e- N)/\\Gamma(\\mu- \\mathrm{capture})$ on aluminum at single-event sensitivity $\\sim 1e-17$ (Mu2e, COMET), versus the SINDRUM II gold limit of about $7e-13$. Combine with $\\mu \\to e\\gamma$ (MEG II) and $\\mu \\to 3e$ (Mu3e) to identify the operator responsible if seen.","problem_ref":null,"references":"","settled_by":"Mu2e at Fermilab and COMET at J-PARC reaching single-event sensitivity near 1e-17.","status_note":"MEG II reported $\\mathrm{BR}(\\mu \\to e \\gamma) < \\sim 1.5e-13$ in 2025 (moderate confidence on the exact value); Mu2e and COMET are expected to start physics running around 2027.","title":"Does muon-to-electron conversion occur at rates near 1e-16?","topic_ref":"bf83146b3162b33e3e47622ed38c05336b0c5694b551ceeb82b1dcacaf745590"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"30971b31bcb17615a08b7ea6a019ddb52df0e431d97357991c6f02f8bb1115a4","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"8f0e8459006dc01944f54ba7fffc511cab65fd5b0176472d420132398b884f35","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"Pm11cflT1JXOeHehqbT4Yk-17nAVJYAP3aB89Yyd4OaB-tHka8tr6OFl8EcuUvr9BDB3O3Xr35wXTJ-dGf3fAA"},"schema":"pubphys.envelope/1"},"record_hash":"30971b31bcb17615a08b7ea6a019ddb52df0e431d97357991c6f02f8bb1115a4","leaf_index":1541}