Search for the Invisible Decay of $J/\ensuremath{\psi}$ in $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$

Search for the Invisible Decay of $J / ψ$ in $ψ (2 S) \to π^{+} π^{-} J / ψ$

M. Ablikim et al. (BES Collaboration)

Phys. Rev. Lett. 100, 192001 – Published 14 May 2008

Abstract

Using $ψ (2 S) \to π^{+} π^{-} J / ψ$ events in a sample of $14.0 \times 10^{6}$ $ψ (2 S)$ decays collected with the BES-II detector, a search for the decay of the $J / ψ$ to invisible final states is performed. No signal is found, and an upper limit at the 90% confidence level is determined to be $1.2 \times 10^{- 2}$ for the ratio $\frac{B (J / ψ \to invisible)}{B (J / ψ \to μ^{+} μ^{-})}$ . This is the first search for $J / ψ$ decays to invisible final states.