{"paper":{"title":"Tests of the Standard Model in $B \\to D\\ell \\nu_\\ell$, $B \\to D^* \\ell \\nu_\\ell$ and $B_c \\to J/\\psi \\, \\ell \\nu_\\ell$","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ex"],"primary_cat":"hep-ph","authors_text":"Henry Lamm, Richard F. Lebed, Thomas D. Cohen","submitted_at":"2018-07-01T02:19:49Z","abstract_excerpt":"A number of recent experimental measurements suggest the possibility of a breakdown of lepton ($\\ell$) universality in exclusive $b \\to c \\ell \\nu_\\ell$ semileptonic meson decays. We analyze the full differential decay rates for several such processes, and show how to extract combinations of the underlying helicity amplitudes that are completely independent of $m_\\ell$. Ratios of these combinations for different $\\ell$ (as well as some combinations for a single value of $\\ell$) therefore equal unity in the Standard Model and provide stringent tests of lepton universality. Furthermore, the extr"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1807.00256","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"}