{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"0eba210cbbbae74b20589a037b70ef82c36db344a53e860aac8e19f15e8a16ce","created":"2026-10-03T07:17:56Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"962a29f2a0636d05b1bbe64e070836727575f94f8f133a012705cc81fc655285","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"beams.polarized-beams.spin-coherence-time","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"Particles with slightly different energies precess at slightly different rates, so a polarized beam slowly loses its common spin direction.","posed_since":"","precise":"Spin decoherence in a ring arises from the spread of spin tune driven by momentum spread and betatron amplitudes. Determine the maximal spin coherence time for protons and deuterons with chromatic sextupole correction and electron cooling, including space charge and intrabeam scattering, relative to the approximately $1e3\\,\\mathrm{s}$ reached for deuterons at the COSY ring (reported 2016).","problem_ref":null,"references":"","settled_by":"Spin-tracking with full beam dynamics validated against COSY data and extended to an EDM-ring lattice.","status_note":"","title":"Maximal spin coherence time of stored hadron beams","topic_ref":"9b02c27128b03f7c327a7c52a19b27e591b0902b0604205d7218c8dbadece62a"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"b5e9bb1a00ed592ba7480cde5ee34781e8420ffdfaca5cc3cbc96c9359897602","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"365d765c7a65d70a130d1e1c07d0feef99c870343b7b1425d738a19af6978d1e","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"8uGFNa0PwtjuSi0XeGc9pld7blS73tm-lCvJ_ADVcVyxQUGV-J0KAZIA_2LwXq3RQjXo1V2hgZGw4id6MUguCA"},"schema":"pubphys.envelope/1"},"record_hash":"b5e9bb1a00ed592ba7480cde5ee34781e8420ffdfaca5cc3cbc96c9359897602","leaf_index":689}