DIRECT MEASUREMENT OF THE W-GAMMA COUPLING AT THE CERN PBARP COLLIDER

The process pp→evγ+X is studied as √s=630 GeV. The observed signal is used to extract a direct measurement of the parameters κ and λ which define the magnetic dipole and electric quadrupole moments of the W boson and therefore the WWγ coupling. We find κ=1+2.6−2.2 and λ=0+1.7−1.8 and their 95% confidence limits −3.5<κ<5.9 and −3.6<λ<3.5. The results are model indepedent and in good agreement with the standard model values, κ=1 and λ=0.