{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"8c841f3fe40890f04c07e852ea2ff70bf839dd47344cef8f1ed067969dd6ccdc","created":"2026-10-03T07:17:56Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"c996f3066df926ddcaebaf65c17ccd6a82dc7d9b4e21fed7dc6e74d7a7f16a16","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"beams.beam-cooling.muon-6d-final-cooling","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"Muons must be squeezed in phase space by a factor of about a million within microseconds, by passing them through absorbers and re-accelerating them; the full chain has never been built.","posed_since":"","precise":"Transverse ionization cooling of muons through a single absorber was demonstrated by MICE (published 2020). Determine whether a realistic 6D cooling channel plus final cooling stage can reach normalized transverse emittance of approximately 2.5e-3 cm and longitudinal emittance of approximately $7\\,\\mathrm{cm}$ with overall muon transmission above $\\sim 10$ percent, including RF limits in solenoid fields, absorber heating, space charge and muon decay.","problem_ref":null,"references":"","settled_by":"An end-to-end simulation with engineering-feasible fields and gradients reaching both emittances, confirmed by a 6D cooling demonstrator for the first stages.","status_note":"","title":"Reaching muon collider target emittances by ionization cooling","topic_ref":"e4bb53556b8c7d13b4b819a20298552b24074d3ba33b0f60982a9bfdd1aa5461"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"dea5b75dcdbb182ed7a0e7fd916ec327dd01d61c06f3a389f15cf952a3454e20","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"f0adfdaf2ea090fd68dd51c6d7f6d15144f4ea110005ed8d56f8639a332987c3","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"nTlNpms36TP8SO4mjt23MUlzBMmBeeFIJc0r7AJJa0LdOK3vkkisMfwhzu9MSds74ximYx_xXT0dgvEzoYW5AQ"},"schema":"pubphys.envelope/1"},"record_hash":"dea5b75dcdbb182ed7a0e7fd916ec327dd01d61c06f3a389f15cf952a3454e20","leaf_index":652}