{"paper":{"title":"Improved Standard-Model prediction for ${K_L\\to \\ell^+\\ell^-}$","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ex","hep-lat","nucl-th"],"primary_cat":"hep-ph","authors_text":"Bai-Long Hoid, Jacobo Ruiz de Elvira, Martin Hoferichter","submitted_at":"2023-10-26T18:00:00Z","abstract_excerpt":"We present a comprehensive calculation of the $K_L\\to\\gamma^*\\gamma^*$ form factor in dispersion theory, using input from the leptonic decays $K_L\\to\\ell^+\\ell^-\\gamma$, $K_L\\to \\ell_1^+\\ell_1^-\\ell_2^+\\ell_2^-$, the hadronic mode $K_L\\to \\pi^+\\pi^-\\gamma$, the normalization $K_L\\to\\gamma\\gamma$, and the matching to asymptotic constraints. As key result we obtain an improved determination of the long-distance contribution to $K_L\\to\\ell^+\\ell^-$, leading to the Standard-Model predictions $\\text{Br}[K_L\\to\\mu^+\\mu^-]=7.44^{+0.41}_{-0.34}\\times 10^{-9}$, $\\text{Br}[K_L\\to e^+e^-]=8.46(37)\\times "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2310.17689","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/2310.17689/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"}