{"paper":{"title":"A Precision Measurement of the Muon Decay Parameters $\\rho$ and $\\delta$","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["nucl-ex"],"primary_cat":"hep-ex","authors_text":"A. Gaponenko, A. Grossheim, A. Hillairet, A. Olin, B. Jamieson, B. Shin, C.A. Gagliardi, D.D. Koetke, D.R. Gill, E.L. Mathie, G.M. Marshall, G. Sheffer, J. Bueno, J. Hu, J.-M. Poutissou, J.R. Musser, K. Olchanski, M.A. Quraan, M.C. Fujiwara, M.D. Hasinoff, M. Nozar, P. Depommier, P. Gumplinger, P. Kitching, R. Bayes, R.E. Mischke, R.E. Tribble, R. Openshaw, R. Poutissou, R.S. Henderson, R. Tacik, T.D.S. Stanislaus, TWIST Collaboration: R.P. MacDonald, V. Selivanov, W. Faszer, Yu.I. Davydov","submitted_at":"2008-07-07T20:52:00Z","abstract_excerpt":"The TWIST collaboration has performed new measurements of two of the parameters that describe muon decay: $\\rho$, which governs the shape of the overall momentum spectrum, and $\\delta$, which governs the momentum dependence of the parity-violating decay asymmetry. This analysis gives the results $\\rho=0.75014\\pm 0.00017(\\text{stat})\\pm 0.00044(\\text{syst})\\pm 0.00011(\\eta)$, where the last uncertainty arises from the correlation between $\\rho$ and the decay parameter $\\eta$, and $\\delta = 0.75067\\pm 0.00030(\\text{stat})\\pm 0.00067(\\text{syst})$. These are consistent with the value of 3/4 given"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0807.1125","kind":"arxiv","version":3},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/0807.1125/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}