{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"a260a5475abd5f7c7033a0ae6ddd1f281c148a8ac49ac719ed3022fee38927b0","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["22717edb7eaa4cca51d6f1f83d7a782cf674c230e840dd8da8f942cc80b2d7a6","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"aa33c3b8814cb4432bc51caa838e6ab79116eab69a67b171f088444757e7719d","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"amo.molecular-parity-violation.first-energy-difference","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"The left- and right-handed forms of a chiral molecule should differ in energy by a tiny amount because of the weak force. No experiment has yet been sensitive enough to see it.","posed_since":"","precise":"$\\Delta E_{\\mathrm{PV}} = E(R) - E(S)$ between enantiomers, or the corresponding difference in a vibrational or rotational transition frequency, $\\Delta \\nu/\\nu$. The best direct bound is at the $10^{-13}$ level of relative frequency for the C-F stretch of CHFClBr (Daussy et al., PRL 1999), several orders of magnitude above predictions for that molecule; heavy-atom candidates (Re, Os, Ru, W complexes, scaling roughly as $Z^5$) are predicted to be larger. An answer is a nonzero $\\Delta \\nu$ or $\\Delta E_{\\mathrm{PV}}$ with significance above $5\\,\\sigma$, with sign and magnitude compared to theory.","problem_ref":"22717edb7eaa4cca51d6f1f83d7a782cf674c230e840dd8da8f942cc80b2d7a6","references":"","settled_by":"Ultrastable-laser vibrational spectroscopy of both enantiomers of a heavy-atom chiral molecule, or a time-resolved measurement of parity evolution in parity-selected states, reaching the predicted $\\Delta E_{\\mathrm{PV}}$.","status_note":"Experiments with cold molecular beams and heavy-atom candidates were still described as progress toward detection in 2025 (Phys. Chem. Chem. Phys. 2025).","title":"First measurement of the parity-violating energy difference between enantiomers","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"f772f8868233471a5c756fa3056554a06feefa28dd078df4581f71881bfb9fd4","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"c4f9cfd85b79ef4b63b46380646e9c86b8b435b28f7859fe4c9e09ee24a39610","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"BJ9t-_pupFiGYUOT1F5IFrb7kvvdYni3ucMBXDjJr8XTbzgSHAKAFzA8HTCJepoIiHU6XqQirw3vrzOCL1nWDg"},"schema":"pubphys.envelope/1"},"record_hash":"f772f8868233471a5c756fa3056554a06feefa28dd078df4581f71881bfb9fd4","leaf_index":2250}