{"paper":{"title":"Search for the rare decays $\\pi^+ \\to \\mu^+\\nu_\\mu\\nu\\bar\\nu$ and $\\pi^+ \\to e^+\\nu_e\\nu\\bar\\nu$","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ph"],"primary_cat":"hep-ex","authors_text":"A. Aguilar-Arevalo, A. Hussein, A. Sher, C. Malbrunot, D.A. Bryman, D. Gorbunov, D.I. Britton, D. Kalashnikov, D. Protopopescu, D. Vavilo, 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":"2020-05-30T23:41:28Z","abstract_excerpt":"The rare pion decays ${\\pi}^+{\\rightarrow}{\\mu}^+{\\nu}_{\\mu}{\\nu}\\bar{\\nu}$ and ${\\pi}^+{\\rightarrow}e^+{\\nu}_{e}{\\nu}\\bar{\\nu}$ are allowed in the Standard Model but highly suppressed. These decays were searched for using data from the PIENU experiment. A first result for ${\\Gamma}({\\pi}^+{\\rightarrow}{\\mu}^+{\\nu}_{\\mu}{\\nu}\\bar{\\nu})/{\\Gamma}({\\pi}^+{\\rightarrow}{\\mu}^+{\\nu}_{\\mu})<8.6{\\times}10^{-6}$, and an improved measurement ${\\Gamma}({\\pi}^+{\\rightarrow}{e}^+{\\nu}_{e}{\\nu}\\bar{\\nu})/{\\Gamma}({\\pi}^+{\\rightarrow}{\\mu}^+{\\nu}_{\\mu})<1.6{\\times}10^{-7}$ were obtained."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2006.00389","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2006.00389/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"}