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

TL;DR

This paper reports the first observation of WW+WZ production in lepton+jets final states at CDF II, using two complementary methods that yield a combined cross section consistent with the Standard Model.

Contribution

It introduces a novel matrix-element based method for measuring WW+WZ production, achieving the first observation in this signature at a hadron collider.

Findings

First observation of WW+WZ in lepton+jets channel

Measured cross section of 16.0 +/- 3.3 pb

Results agree with Standard Model predictions

Abstract

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.