{"paper":{"title":"Strong $U_A(1)$ breaking in radiative $\\eta$ decays","license":"","headline":"","cross_cats":[],"primary_cat":"hep-ph","authors_text":"M. Oka (Department of Physics, M. Takizawa (Institute for Nuclear Study, Tokyo Institute of Technology), University of Tokyo), Y. Nemoto","submitted_at":"1996-08-22T05:06:51Z","abstract_excerpt":"We study the \\egg, \\egm and \\epg decays using an extended three-flavor Nambu-Jona-Lasinio model that includes the 't~Hooft instanton induced interaction. We find that the $\\eta$-meson mass, the \\egg, \\egm and \\epg decay widths are in good agreement with the experimental values when the $U_{A}(1)$ breaking is strong and the flavor $SU(3)$ singlet-octet mixing angle $\\theta$ is about zero. The calculated $\\eta \\gamma \\gamma^\\ast$ transition form factor has somewhat weaker dependence on the squared four-momentum of the virtual photon. The effects of the $U_A(1)$ anomaly on the scalar quark conten"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"hep-ph/9608403","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":""},"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"}