{"paper":{"title":"Axial anomaly and the precise value of the $\\pi^0 \\to 2 \\gamma$ decay width","license":"","headline":"","cross_cats":[],"primary_cat":"hep-ph","authors_text":"A.G.Oganesian, B.L.Ioffe","submitted_at":"2007-01-10T13:58:49Z","abstract_excerpt":"The anomaly in the vacuum expectation value of the product of axial and two vector currents (AVV) in QCD is investigated. The goal is to determine from its value the $\\pi^0 \\to 2 \\gamma$ decay width with high precision. The sum rule for AVV formfactor is studied. The difference $f_{\\pi^0} - f_{\\pi^+}$ caused by strong interaction is calculated and appears to be small. The $\\pi^0 - \\eta$ mixing is accounted. The $\\pi^0 \\to 2 \\gamma$ decay width determined theoretically from the axial anomaly is found to be $\\Gamma(\\pi^0 \\to 2 \\gamma) = 7.93 eV$ with an error $\\sim 1.5%$. The measurement of the "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"hep-ph/0701077","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/hep-ph/0701077/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"}