Search for $ψ(4S)\toηJ/ψ$ in $B^\pm \ra ηJ/ψK^\pm$ and $e^+ e^- \to ηJ/ψ$ processes

Abstract

We search for the $ψ(4S)$ state in $B^\pm \ra ηJ/ψK^\pm$ and $e^+e^- \ra ηJ/ψ$ based on the Belle measurements with the assumed mass $M=(4230\pm8)$ MeV/$c^2$ and width $Γ=(38\pm12)$ MeV. No significant signal is observed in the $ηJ/ψ$ mass spectra. The 90\% confidence level upper limit on the product branching fraction $\BR(B^\pm \ra ψ(4S)K^\pm)\BR(ψ(4S) \ra ηJ/ψ)<6.8\times 10^{-6}$ is obtained in $B^\pm \ra ηJ/ψK^\pm$ decays. By assuming the partial width of $ψ(4S) \to e^+e^-$ being 0.63 keV, the branching fraction limit $\BR(ψ(4S) \ra ηJ/ψ) < 1.3\%$ is obtained at the 90\% confidence level in $e^+e^- \ra ηJ/ψ$, which is consistent with the theoretical prediction.