Search for New Particles ine+e−Annihilation from 39.79 to 45.52 GeV

Abstract

We have searched for resonances in the reaction $e^{+}{e}^{-}\to \mathrm{hadrons}, \gamma \gamma , \mu \mu , \mathrm{and} \mathrm{ee}$, in the energy range $39.79<\mathrm{}\sqrt{s}<45.52\mathrm{}$ GeV, using the Mark J detector at PETRA. We obtain stringent upper limits on the production of toponium and particles postulated to explain $Z^0\to \mathrm{lepton}\mathrm{pair}+\gamma$ events observed at the CERN $\bar{p}p$ collider. We also set limits on the mass and coupling constant of excited electrons.