Neutrino tridents and<i>W</i>-<i>Z</i>interference

We present a measurement of neutrino tridents, muon pairs induced by neutrino scattering in the Coulomb field of a target nucleus, in the Columbia-Chicago-Fermilab-Rochester neutrino experiment at the Fermilab Tevatron. The observed number of tridents after geometric and kinematic corrections, 37.0\ifmmode\pm\else\textpm\fi{}12.4, supports the standard-model prediction of 45.3\ifmmode\pm\else\textpm\fi{}2.3 events. This is the first demonstration of the W-Z destructive interference from neutrino tridents, and rules out, at 99% C.L., the V-A prediction without the interference.