{"paper":{"title":"New Experimental Constraints for the Standard Model from Muon Decay","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"hep-ex","authors_text":"A. Gaponenko, A. Grossheim, A. Hillairet, A. Olin, B. Shin, C.A. Gagliardi, D.D. Koetke, D.R. Gill, E.L. Mathie, G.M. Marshall, G. Sheffer, J.F. Bueno, J. Hu, J.-M. Poutissou, K. Olchanski, M.D. Hasinoff, P. Depommier, P. Gumplinger, R. Bayes, R.E. Mischke, R.E. Tribble, R. Openshaw, R.P. MacDonald, R. Poutissou, R.S. Henderson, R. Tacik, T.D.S. Stanislaus, V. Selivanov, W. Faszer, Yu.I. Davydov","submitted_at":"2010-10-24T20:18:39Z","abstract_excerpt":"The TWIST Collaboration has completed a new measurement of the energy-angle spectrum of positrons from the decay of highly polarized muons. A simultaneous measurement of the muon decay parameters {\\rho}, {\\delta}, and (P_{\\mu}){\\xi} tests the Standard Model (SM) in a purely leptonic process and provides improved limits for relevant extensions to the SM. Specifically, for the generalized left-right symmetric model |(g_R/g_L){\\zeta}|<0.020 and (g_L/g_R)m_2> 578 GeV/c^2, both 90% C.L."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1010.4998","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"}