Search for single photons from radiative neutrino or supersymmetric-particle production

A search for single photons produced in association with neutrinos or other weakly interacting neutral particles has been performed in e/sup +/e/sup -/ annihilations at ..sqrt..s = 29 GeV with MAC detector at the SLAC e/sup +/e/sup -/ storage ring PEP. One event is observed, with 1.1 events expected from the reaction e/sup +/e/sup -/..--> nu..nu-bar..gamma... The number of neutrino families is restricted to N/sub ..nu../48 GeV/c/sup 2/ at the 90% confidence level if m/sub e//sub L/ = m/sub e//sub R/ and m/sub gamma-tilde/ = 0. If m/sub e//sub L/>>m/sub e//sub R/, the corresponding limit is m/sub e//sub R/>40 GeV/c/sup 2/.