Measurement of the WW+WZ production cross section using a matrix element technique in lepton+jets events

We present a measurement of the WW + WZ production cross section observed in a final state consisting of an identified electron or muon, two jets, and missing transverse energy. The measurement is carried out in a data sample corresponding to up to 4.6 fb{sup -1} of integrated luminosity at {radical}s = 1.96 TeV collected by the CDF II detector. Matrix element calculations are used to separate the diboson signal from the large backgrounds. The WW + WZ cross section is measured to be 17.4 {+-} 3.3 pb, in agreement with standard model predictions. A fit to the dijet invariant mass spectrum yields a compatible cross section measurement.