{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"7075289146d61ba9628930b0fa217e9741837ddf232da74675a0e4c0c79a6cd7","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b","e256dea0e0dbb033f8de50ce8ab972920cda3950ac0e844cb0d8a014c57f4cc8"],"salt":"77f5500b596f18cf2342c074968ef9b0d11895ead3f288ebee0bd1bd4ed6f817","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":"2","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 $10^{-12}$ level, using sympathetic or quantum-logic cooling for faster single-spin-flip detection.","problem_ref":"e256dea0e0dbb033f8de50ce8ab972920cda3950ac0e844cb0d8a014c57f4cc8","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 $10^{-12}$","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"ec6ad7f46f65b4e3db15dd604af6040e50bad09fd5b67ec11c56a447854a6775","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"332ebd6add9b6c5c3808d8e3a0b76769d2e7c7c894668c0f6ef1f6df84578840","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"WqJ3KAEn3ikgX23EenFWBAmGctW-WYtwaqGYwWk3ZCvieGPA7WXXfE2Cjr3cBP2xxzqsYkd3M_gWwlsOWjOkAQ"},"schema":"pubphys.envelope/1"},"record_hash":"ec6ad7f46f65b4e3db15dd604af6040e50bad09fd5b67ec11c56a447854a6775","leaf_index":2242}