Model-independent bounds on R(J/ψ)

• DOI: 10.1007/jhep09(2018)168
• Publication Date: 2018-09-29T05:26:41Z
• Authors: Thomas D. Cohen; Henry Lamm; Richard F. Lebed
• Keywords: High Energy Physics - Phenomenology; High Energy Physics - Lattice; Nuclear Theory; Nuclear and particle physics. Atomic energy. Radioactivity; 0103 physical sciences; Heavy Quark Physics; Lattice QCD; QC770-798; 01 natural sciences; Quark Masses and SM Parameters; High Energy Physics - Experiment

Abstract

We present a model-independent bound on

$$ R\left(J/\psi \right)\equiv \mathrm{\mathcal{B}}\mathrm{\mathcal{R}}\left({B}_C^{+}\to J/\psi {\tau}^{+}{\nu}_{\tau}\right)/\mathrm{\mathcal{B}}\mathrm{\mathcal{R}}\left({B}_C^{+}\to J/\psi {\mu}^{+}{\nu}_{\mu}\right) $$

R

J / ψ

≡ ℬ ℛ

B C +

→ J / ψ

τ +

ν τ

/ ℬ ℛ

B C +

→ J / ψ

µ +

ν µ

. 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.