Experimental limit on the decay W±→π±γ at the cern proton-antiproton collider

We present a search for the decay W±→π±γ, using data taken at the CERN proton-antiproton Collider with the UA1 detector and corresponding to an integrated luminosity of 0.7 pb−1. We do not observe a signal for such a process: hence we obtain an upper limit on the π±γ decay width of 5.8×10−2Γ (W±→e±v) (95%CL).