Search for the Higgs boson in the H->WW->lvjj decay channel using 4.7 fb-1 of pp collisions at sqrt{s} = 7 TeV with the ATLAS detector

A search for the Standard Model (SM) Higgs boson has been performed in the $H\rightarrow WW\rightarrow\ell\nu jj$ channel in 4.7 ${\rm fb}^{-1}$ of $pp$ collision data at $\sqrt{s} = 7~{\rm TeV}$ recorded with the ATLAS detector at the Large Hadron Collider. Higgs boson candidates produced in association with zero, one, or two jets are included in the analysis to maximize the acceptance for both gluon fusion and weak boson fusion Higgs boson production processes. No significant excess of events is observed over the expected background and limits on the Higgs boson production cross section are derived for a Higgs boson mass in the range $300~{\rm GeV}<\mH<600$~GeV. The best sensitivity is reached for $\mH = 400\GeV$, where the observed (expected) 95\% confidence level upper bound on the cross section for $H\rightarrow WW$ produced in association with zero or one jet is 2.7 pb (1.9 pb), corresponding to 2.3 (1.6) times the SM prediction. The channel of the Higgs produced in association with two forward jets is sensitive to the weak boson fusion process. In the Higgs boson plus two jets channel, the observed (expected) 95\% confidence level upper bound on the cross section for $H\rightarrow WW$ production with $\mH = 400\GeV$ is 0.93 pb (0.7 pb), corresponding to 9.8 (7.4) times the SM prediction. This analysis represents the first search by the ATLAS Collaboration for SM Higgs boson production via weak boson fusion in the $\ell\nu jj$ channel.