{"paper":{"title":"Nab: Measurement Principles, Apparatus and Uncertainties","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ex","hep-ph"],"primary_cat":"nucl-ex","authors_text":"A. Klein, A. Palladino, A.R. Young, C. Crawford, D. Pocanic, E. Frlez, F.W. Hersman, G.L. Greene, G.R. Young, J. Byrne, J.D. Bowman, J. Martin, J.R. Calarco, K.P. Rykaczewski, L.P. Alonzi, M.A. Bychkov, M.T. Gericke, R. Alarcon, R.K. Grzywacz, S.A. Page, S. Baessler, S. Balascuta, S.I. Penttila, V. Cianciolo, V. Gudkov, W.S. Wilburn","submitted_at":"2008-10-01T19:46:55Z","abstract_excerpt":"The Nab collaboration will perform a precise measurement of 'a', the electron-neutrino correlation parameter, and 'b', the Fierz interference term in neutron beta decay, in the Fundamental Neutron Physics Beamline at the SNS, using a novel electric/magnetic field spectrometer and detector design. The experiment is aiming at the 10^{-3} accuracy level in (Delta a)/a, and will provide an independent measurement of lambda = G_A/G_V, the ratio of axial-vector to vector coupling constants of the nucleon. Nab also plans to perform the first ever measurement of 'b' in neutron decay, which will provid"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0810.0251","kind":"arxiv","version":1},"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"}