{"paper":{"title":"Dispersive analysis for $\\eta\\to \\gamma\\gamma^*$","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["nucl-th"],"primary_cat":"hep-ph","authors_text":"A. Kupsc, A. Wirzba, C. Hanhart, F. Stollenwerk, U.-G. Mei{\\ss}ner","submitted_at":"2013-07-22T11:11:06Z","abstract_excerpt":"A dispersion integral is derived that connects data on $\\eta\\to \\pi^+\\pi^-\\gamma$ to the $\\eta\\to \\gamma\\gamma^*$ transition form factor. A detailed analysis of the uncertainties is provided. We find for the slope of the $\\eta$ transition form factor at the origin $b_\\eta = (2.05 {}^{+0.22}_{-0.10})\\, {\\rm GeV}^{-2}$. Using an additional, plausible assumption, one finds for the corresponding slope of the $\\eta'$ transition form factor, $b_{\\eta'} = (1.58 {}^{+0.15}_{-0.08})\\, {\\rm GeV}^{-2}$. Both values are consistent with all recent data, but differ from some previous theoretical analyses."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1307.5654","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"}