Search for MoreJParticles

We report here on an experiment done at the 30-GeV proton synchrotron at Brookhaven National Laboratory using a large-acceptance ($\Delta m=1\mathrm{}$ GeV) pair spectrometer with a mass resolution of ±5 MeV, to search for additional long-lived particles which decay into $K^{-}{\pi }^{+}$, $K^{+}{\pi }^{-}$, $\overline{p}p$, $K^{+}{K}^{-}$, ${\pi }^{+}{\pi }^{-}$, $K^{-}p$, ${\pi }^{-}p$, $K^{+}\overline{p}$, or ${\pi }^{+}\overline{p}$. The result, based on 2×${10}^7$ events, shows that, to a sensitivity comparable to or lower than the production of $J$ particles [(production) × (decay branching ratio) ≈ ${10}^{-34\mathrm{}}$ ${\mathrm{cm}}^2$], no additional states were found.