Model-independent bounds on R(J/ψ)

Thomas D. Cohen, Henry Lamm, Richard Lebed

Research output: Contribution to journalArticle

15 Scopus citations


We present a model-independent bound on R(J/ψ)≡ℬℛ(BC+→J/ψτ+ντ)/ℬℛ(BC+→J/ψµ+νµ). This bound is constructed by constraining the form factors through a combination of dispersive relations, heavy-quark relations at zero-recoil, and the limited existing determinations from lattice QCD. The resulting 95% confidence-level bound, 0.20 ≤ R(J/ψ) ≤ 0.39, agrees with the recent LHCb result at 1.3σ, and rules out some previously suggested model form factors.

Original languageEnglish (US)
Article number168
JournalJournal of High Energy Physics
Issue number9
StatePublished - Sep 1 2018



  • Heavy Quark Physics
  • Lattice QCD
  • Quark Masses and SM Parameters

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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