{"paper":{"title":"Model-Independent Bounds on $R(J/\\psi)$ via Dispersive Relations","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ex","hep-lat"],"primary_cat":"hep-ph","authors_text":"Henry Lamm","submitted_at":"2018-09-21T17:52:02Z","abstract_excerpt":"Model-independent bounds on $R(J/\\psi) \\! \\equiv \\!\\mathcal{BR} (B_c^+ \\rightarrow J/\\psi \\, \\tau^+\\nu_\\tau)/$ $\\mathcal{BR} (B_c^+ \\rightarrow J/\\psi \\, \\mu^+\\nu_\\mu)$ are obtained through a combination of dispersive relations, heavy-quark relations at zero-recoil, and the limited existing form factor determinations from lattice QCD. The resulting 95% confidence-level bound, $0.20\\leq R(J/\\psi)\\leq0.39$, agrees with the recent LHCb result at $1.3 \\, \\sigma$, and removes the dominant model-dependent uncertainty from theory predictions. Using the same techniques, a prediction of $R(\\eta_c)=0.29"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1809.08227","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"}