{"paper":{"title":"Neutral Pion Lifetime Measurements and the QCD Chiral Anomaly","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ex","nucl-ex","nucl-th"],"primary_cat":"hep-ph","authors_text":"A. M. Bernstein, Barry R. Holstein","submitted_at":"2011-12-20T19:46:21Z","abstract_excerpt":"A fundamental property of QCD is the presence of the chiral anomaly, which is the primary component of the $\\pi^0\\rightarrow\\gamma\\gamma$ decay amplitude. Based on this anomaly and its small ($\\simeq$ 4.5%) chiral correction, a firm prediction of the $\\pi^0$ lifetime can be used as a test of QCD at confinement scale energies. The interesting experimental and theoretical histories of the $\\pi^0$ meson are reviewed, from discovery to the present era. Experimental results are in agreement with the theoretical prediction, within the current ($\\simeq$ 3%) experimental error; however, they are not y"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1112.4809","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":""},"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"}