{"paper":{"title":"Precision Measurements and CKM Unitarity","license":"","headline":"","cross_cats":[],"primary_cat":"hep-ph","authors_text":"Alberto Sirlin, Andrzej Czarnecki, William J. Marciano","submitted_at":"2004-06-29T14:25:39Z","abstract_excerpt":"Determinations of $\\vud$ and $\\vus$ along with their implications for the unitarity test $\\vud^2+\\vus^2+\\vub^2=1$ are discussed. The leading two loop radiative corrections to neutron $\\beta$-decay are evaluated and used to derive a refined relationship $\\vud^2 \\tau_n (1+3g_A^2)=4908(4)$sec. Employing $\\vud =0.9740(5)$ from superallowed nuclear decays and the measured neutron lifetime $\\tau_n = 885.7(7)$sec, leads to the precise prediction $g_A=1.2703(8)$ which is compared with current direct experimental values. Various extractions of $\\vus$ are described and updated. The long accepted Particl"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"hep-ph/0406324","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}