{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"d80e4688f0baa4cb4bdb9ef77e75817ccca2814cf32bf01a9964dcf345925de3","created":"2026-10-03T07:17:53Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"c03ff151749742283da0338632e85f3efff029af0db224c02e83afd9fa34a931","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"amo.lorentz-cpt.antiproton-moment","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"A single proton or antiproton held in an electromagnetic trap can have its magnetism measured by flipping its spin. Matter-antimatter symmetry requires the two magnetic moments to be equal and opposite.","posed_since":"","precise":"BASE compared proton and antiproton charge-to-mass ratios to 16 ppt (2022) and magnetic moments to about 1.5 ppb (2017). Determine whether $\\left|\\mu_{\\mathrm{pbar}}\\right|/\\mu_{\\mathrm{p}} - 1$ is nonzero at the 1e-12 level, using sympathetic or quantum-logic cooling for faster single-spin-flip detection.","problem_ref":null,"references":"","settled_by":"Penning-trap measurements of the proton and antiproton g-factors each at sub-ppt uncertainty.","status_note":"","title":"Proton and antiproton magnetic moments compared at 1e-12","topic_ref":"a6fc573c8db5bce913b8300d4956b1137cedf47b39c553b8063ed7baf3f179b3"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"e256dea0e0dbb033f8de50ce8ab972920cda3950ac0e844cb0d8a014c57f4cc8","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"9399763e88bd4325429fcf6aba27d1c27d6ef38a9c4d0c09c1a9ab143e70a00b","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"qUMeQPgwuhwsPeip5a2-Xk1fVQX5CBjqS8Y2GElbBSmURpA32mVX6tbXlBf7hIRiV7mKYg2jH7ZWoCieMuneCg"},"schema":"pubphys.envelope/1"},"record_hash":"e256dea0e0dbb033f8de50ce8ab972920cda3950ac0e844cb0d8a014c57f4cc8","leaf_index":420}