{"paper":{"title":"The puzzle of the \\pi -> \\gamma \\gamma* transition form factor","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"hep-ph","authors_text":"Dmitri Melikhov, Wolfgang Lucha","submitted_at":"2011-10-10T15:43:38Z","abstract_excerpt":"We study the $P\\to\\gamma\\,\\gamma^*$ ($P=\\pi^0,\\eta,\\eta'$) transition form factors by means of the local-duality (LD) version of QCD sum rules. For the case of $\\eta$ and $\\eta'$, the conventional LD model provides a good description of the existing data. However, for the $\\pi$ form factor we find disagreement with recent BaBar results for high $Q^2$ even though the accuracy of the LD approximation is expected to increase with $Q^2$. It remains mysterious why the $\\eta$ and $\\eta'$ form factors to virtual photons, on the one hand, and the $\\pi$ form factor, on the other hand, show a qualitativ"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1110.2080","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"}