Search for a high-mass Higgs boson in the $H \rightarrow WW \rightarrow l\nu l\nu$ decay channel with the ATLAS detector using 21 fb$^{-1}$ of proton-proton collision data

A search by the ATLAS experiment at the Large Hadron Collider for a Higgs boson in the $H \rightarrow WW \rightarrow \ell\nu \ell\nu$ channel in the range 260 GeV $<~m_H~<$ 1 TeV is presented. The analysis uses proton-proton collision data at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 20.7 fb$^{-1}$. A Higgs boson with Standard Model-like couplings is excluded at 95\% confidence level in the mass range 260 GeV $<m_H<$ 642 GeV.