{"paper":{"title":"Search for lepton number and flavour violation in $K^{+}$ and $\\pi^{0}$ decays","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"hep-ex","authors_text":"NA62 collaboration","submitted_at":"2021-05-14T11:04:47Z","abstract_excerpt":"Searches for the lepton number violating $K^{+} \\rightarrow \\pi^{-} \\mu^{+} e^{+}$ decay and the lepton flavour violating $K^{+} \\rightarrow \\pi^{+} \\mu^{-} e^{+}$ and $\\pi^{0} \\rightarrow \\mu^{-} e^{+}$ decays are reported using data collected by the NA62 experiment at CERN in $2017$-$2018$. No evidence for these decays is found and upper limits of the branching ratios are obtained at 90% confidence level: $\\mathcal{B}(K^{+}\\rightarrow\\pi^{-}\\mu^{+}e^{+})<4.2\\times 10^{-11}$, $\\mathcal{B}(K^{+}\\rightarrow\\pi^{+}\\mu^{-}e^{+})<6.6\\times10^{-11}$ and $\\mathcal{B}(\\pi^{0}\\rightarrow\\mu^{-}e^{+})<"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2105.06759","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2105.06759/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"}