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

A bstract 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 {\mu}^{+}{\nu}_{\mu}\right) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>R</mml:mi> <mml:mfenced> <mml:mrow> <mml:mi>J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> </mml:mrow> </mml:mfenced> <mml:mtext>≡</mml:mtext> <mml:mi>ℬ</mml:mi> <mml:mi>ℛ</mml:mi> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>C</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>τ</mml:mi> </mml:msup> <mml:msub> <mml:mi>ν</mml:mi> </mml:msub> <mml:mi>µ</mml:mi> </mml:math> . This is constructed by constraining the form factors through combination of dispersive relations, heavy-quark relations at zero-recoil, and limited existing determinations from lattice QCD. The resulting 95% confidence-level bound, 0.20 ≤ R ( J / ψ ) 0.39, agrees with recent LHCb result 1.3 σ , rules out some previously suggested model factors.