Following reports of anomalous dielectron prediction in the mass region near 6 GeV at 400 GeV, we searched for an enhancement in the reaction $e^{+}{e}^{-}\to \mathrm{hadrons}$ and $e^{+}{e}^{-}\to e^{+}{e}^{-}$ at SPEAR in the center-of-mass energy range 5.67-6.43 GeV. The leptonic and hadronic cross sections show no statistically significant peaks. In this mass range, 95% confidence level upper limits for the decay width into electron pairs are less than 200 eV for a narrow resonance which decays predominantly either into hadrons or into electron pairs.

• Received 4 February 1977

DOI:https://doi.org/10.1103/PhysRevLett.39.124