Bounding the Tau Neutrino Magnetic Moment from Single Photon Searches at   LEP
  We show that single photon searches at LEP constrain the tau neutrino magnetic moment to be less than ${\cal O}(10^{-6})~\mu_B$. This bound is competitive with low energy ($s\simeq (30~GeV)^2$) single photon searches. 
Thomas M. Gould and I.Z Rothstein