Measurement of the anomalous magnetic and electric dipole moments of the tau lepton

We analyse e+e−→ττγ events using 100pb−1 of data collected by the L3 experiment during the 1991-1995 LEP runs at the Z pole. From the energy of the photons and their isolation from the tau decay products, we determine the anomalous magnetic and electric dipole moments of the tau to be, respectively:aτ=0.004±0.027±0.023;dτ=(0.0±1.5±1.3)×10−16e·cm.This is a direct measurement of these τ form factors at q2=0.