A search for the Standard Model Higgs boson decaying to two W bosons with the subsequent decay to a final state containing one lepton, one neutrino, and two (or three) jets ($H\rightarrow WW^{*}\rightarrow\ell\nu

jj$ where ℓ stands for electron or muon) is presented using 4.7~fb−1 of data recorded by the ATLAS detector in 2011

at center of mass energy s= 7~TeV. No significant excess is observed over the expected Standard Model background.

Limits on the Higgs production cross section are derived for masses between \mH = 300 GeV and \mH = 600 GeV. For a Higgs

boson mass \mH = 400~GeV, the 95% confidence level upper bound on the cross-section for Higgs boson production by gluon fusion times the

branching ratio for H→WW∗ is 2.2 pb, or approximately 1.9 times the Standard Model prediction.