First Study of the Radiation-Amplitude Zero inWγProduction and Limits on AnomalousWWγCouplings ats=1.96TeV

We present results from a study of $p\overline{p}\to W\gamma +X$ events utilizing data corresponding to $0.7{\mathrm{fb}}^{-1}$ of integrated luminosity at $\sqrt{s}=1.96\mathrm{TeV}$ collected by the D0 detector at the Fermilab Tevatron Collider. We set limits on anomalous $WW\gamma$ couplings at the 95% C.L. The one-dimensional 95% C.L. limits are $0.49<{\kappa }_{\gamma }<1.51$ and $-0.12<{\lambda }_{\gamma }<0.13$. We make the first study of the charge-signed rapidity difference between the lepton and the photon and find it to be indicative of the standard model radiation-amplitude zero in the $W\gamma$ system.