{"paper":{"title":"Positron-Emitting and Electron-Capturing Double-Beta Processes in the Standard Model and Beyond","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["nucl-ex","nucl-th"],"primary_cat":"hep-ph","authors_text":"Jenni Kotila, Luk\\'a\\v{s} Gr\\'af, Oliver Scholer","submitted_at":"2026-06-24T17:59:59Z","abstract_excerpt":"We study positron-emitting and electron-capturing double-beta-decay modes as probes complementary to the usual double beta decay. Motivated by the proposed NuDoubt++ experiment, we analyze the candidate isotopes ${}^{78}$Kr, ${}^{106}$Cd, and ${}^{124}$Xe, providing nuclear matrix elements and phase-space factors for both neutrinoful and neutrinoless modes. For the Standard-Model channels, we find that $2\\nu$ECEC and $2\\nu\\beta^+$EC are the most experimentally accessible, whereas $2\\nu\\beta^+\\beta^+$ remains strongly phase-space suppressed. For the neutrinoless channel, we interpret a projecte"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2606.26097","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/2606.26097/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"}