New results on single-photon production at√s= 29 GeV

This Letter reports results of a search for radiative production, by e⁺{e}^{{{-}}}$ annihilation of particles that interact only weakly in matter. The search has been made in the total data set of 115 ${pb}^{{{-}}1}$ acquired with the ASP detector at the SLAC storage ring PEP (s=29 GeV). No anomalous signal was observed. The number of generations of light neutrinos has been limited to ${N}_{{ν}}$7.5 (90% confidence level). Limits are also placed on the masses of particles predicted to exist by models of supersymmetry.