Measurement of the WW+WZ Production Cross Section Using the Lepton+Jets Final State at CDF II

Understand

We report two complementary measurements of the WW+WZ cross section in the final state consisting of an electron or muon, missing transverse energy, and jets, performed using p\bar{p} collision data at sqrt{s} = 1.96 TeV collected by the CDF II detector.

• The first method uses the dijet invariant mass distribution while the second more sensitive method uses matrix-element calculations.
• The result from the second method has a signal significance of 5.4 sigma and is the first observation of WW+WZ production using this signature.
• Combining the results gives sigma_{WW+WZ} = 16.0 +/- 3.3 pb, in agreement with the standard model prediction.