{"paper":{"title":"The derivative of the topological susceptibility at zero momentum and an estimate of $\\eta'$ mass in the chiral limit","license":"","headline":"","cross_cats":[],"primary_cat":"hep-ph","authors_text":"A. Upadhyay, J. Pasupathy, J. P. Singh, R. K. Singh","submitted_at":"2005-09-23T12:54:11Z","abstract_excerpt":"The anomaly-anomaly correlator is studied using QCD sum rules. Using the matrix elements of anomaly between vacuum and pseudoscalars $\\pi, eta$ and $\\eta'$, the derivative of correlator $chi'(0)$ is evaluated and found to be $\\approx 1.82 \\times 10^{-3}$ GeV$^2$. Assuming that $\\chi'(0)$ has no significant dependence on quark masses, the mass of $\\eta'$ in the chiral limit is found to be $\\approx$723 MeV. The same calculation also yields for the singlet pseudoscalar decay constant in the chiral limit a value of $\\approx 178$ MeV."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"hep-ph/0509260","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"}