{"paper":{"title":"Improved Search for Heavy Neutrinos in the Decay $\\pi\\rightarrow e\\nu$","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"hep-ex","authors_text":"A. Aguilar-Arevalo, A. Hussein, A. Sher, C. Malbrunot, D.A. Bryman, D.I. Britton, D. Protopopescu, D. Vavilov, D. vom Bruch, J. Comfort, L. Doria, L. Kurchaninov, L.S. Littenberg, M. Aoki, M. Blecher, P. Gumplinger, R.E. Mischke, S. Chen, S. Cuen-Rochin, S. Ito, S. Kettell, T. Numao, T. Sullivan, Y. Igarashi","submitted_at":"2017-12-08T20:38:31Z","abstract_excerpt":"A search for massive neutrinos has been made in the decay $\\pi\\rightarrow e^+ \\nu$. No evidence was found for extra peaks in the positron energy spectrum indicative of pion decays involving massive neutrinos ($\\pi\\rightarrow e^+ \\nu_h$). Upper limits (90 \\% C.L.) on the neutrino mixing matrix element $|U_{ei}|^2$ in the neutrino mass region 60--135 MeV/$c^2$ were set, which are %representing an order of magnitude improvement over previous results."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1712.03275","kind":"arxiv","version":4},"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"}