{"paper":{"title":"Precision measurement of the $\\beta$-asymmetry in spin-polarized $^{37}\\mathrm{K}$ decay","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"nucl-ex","authors_text":"A. Gorelov, B. Fenker, C.L. Warner, D. Ashery, D. Melconian, G. Gwinner, I. Cohen, I. Craiciu, J.A. Behr, J. McNeil, K. Olchanski, M. Anholm, M. Mehlman, P.D. Shidling, R.S. Behling, S. Smale","submitted_at":"2017-06-01T17:55:25Z","abstract_excerpt":"Using TRIUMF's neutral atom trap, TRINAT, for nuclear $\\beta$ decay, we have measured the $\\beta$ asymmetry with respect to the initial nuclear spin in $^{37}\\mathrm{K}$ to be $A_\\beta=-0.5707(13)_\\mathrm{syst}(13)_\\mathrm{stat}(5)_\\mathrm{pol}$, a 0.3% measurement. This is the best relative accuracy of any $\\beta$-asymmetry measurement in a nucleus or the neutron, and is in agreement with the standard model prediction $-0.5706(7)$. We compare constraints on physics beyond the standard model with other $\\beta$-decay measurements, and improve the value of $V_\\mathrm{ud}$ measured in this mirror"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1706.00414","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"}