{"paper":{"title":"One-loop determination of $\\tau \\to \\pi (K) \\nu_{\\tau}[\\gamma]$ branching ratios and new physics tests","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"hep-ph","authors_text":"G. Hern\\'andez-Tom\\'e, G. L\\'opez-Castro, I. Rosell, M.A. Arroyo-Ure\\~na, P. Roig","submitted_at":"2021-12-03T11:30:53Z","abstract_excerpt":"We calculate the ratios $R_{\\tau / P}\\equiv \\Gamma \\left( \\tau \\to P \\nu_{\\tau}[\\gamma] \\right) / \\Gamma \\left(P\\to \\mu \\nu_{\\mu}[\\gamma]\\right)$ ($P=\\pi,K$) at one loop following a large-$N_C$ expansion where Chiral Perturbation Theory is enlarged by including the lightest resonances and respecting the short-distance behavior dictated by QCD. We find $\\delta R_{\\tau/\\pi}=(0.18\\pm 0.57 )\\%$ and $\\delta R_{\\tau/K}=(0.97\\pm 0.58 )\\%$, where the uncertainties are induced fundamentally by the counterterms. We test the lepton universality, obtaining $\\left|g_\\tau/g_\\mu\\right|_\\pi=0.9964\\pm 0.0038$ "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2112.01859","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2112.01859/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}