{"paper":{"title":"First observation of KL -> pi+- e-+ nu e+ e-","license":"","headline":"","cross_cats":[],"primary_cat":"hep-ex","authors_text":"KTeV Collaboration","submitted_at":"2007-05-22T09:54:26Z","abstract_excerpt":"This letter is the first report of the KL -> pi+- e-+ nu e+ e- decay. Based on 19208+-144 events, we determine the branching fraction, B(KL -> pi+- e-+ nu e+ e-; Mee > 5 MeV/c^2, E*ee > 30 MeV) = (1.285+-0.041)x10^-5, and Gamma(Ke3ee; Mee >5 MeV/c^2) / Gamma(Ke3) = [4.57+-0.04(stat)+-0.14(syst)]x10^-5. This ratio agrees with a theoretical prediction based on chiral perturbation theory (ChPT) calculated to O(p^4). The measured kinematical distributions agree with those predicted by just ChPT O(p^4), but show significant disagreement with ones predicted by leading order ChPT."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0705.3108","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":""},"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"}