Search for Monojet Production ine+e−Annihilation

A search for monojet production in $e^{+}{e}^{-}$ annihilation has been performed at $\sqrt{s}=29\mathrm{}$ GeV with the MAC detector at PEP. No events beyond those expected from tau decays have been found. The result has been interpreted as an upper limit for $Z^0$ decays into monojets, giving an upper limit for the branching ratio of 0.5% at the 90% confidence level. This limit excludes an interpretation that the monojets discovered by Arnison et al. are due to $Z^0$ decays into light Higgs pairs.