Search for associated production of a W and a Higgs Boson in $\ell\nu b\bar{b}$ final states at D0

A search for $WH$ production on $p\bar{p}$ collisions performed by the D0 collaboration at a center of mass energy of $\sqrt{s} = 1.96$ TeV is presented. Events selected for this analysis are required to have one lepton (electron or muon), missing transverse energy, and one or two $b$-tagged jets. Significant improvements to the sensitivity of the analysis to a Higgs signal have been made in the areas of lepton identification, $b$-jet identification, and separation of signal and multi-jet background. We describe these improvements and present upper limits on the Standard Model Higgs production cross section.