Beyond the Standard Model Higgs search at High Mass in the H->ZZ->llqq channel with the ATLAS detector at LHC

A search for a high-mass Higgs boson in the H->ZZ->llqq channel using the ATLAS detector at the CERN Large Hadron Collider is presented. The search uses proton–proton collision data at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 20.3 fb^-1. The results of the search are interpreted in the scenario of a heavy Higgs boson with a width that is small compared with the experimental mass resolution. The Higgs boson mass range considered extends between 200 GeV and 1000 GeV. No significant excess of events over the Standard Model prediction is found. Upper limits on the production cross-section of a heavy Higgs boson times the branching ratio are extracted. 95% confidence level upper limits range from 3.33 pb at m(H) = 200 GeV to 0.03 pb at m(H) = 1 TeV for the gluon-gluon fusion production mode and from 0.45 pb at m(H) = 200 GeV to 0.02 pb at m(H) = 1 TeV for the vector-boson fusion production mode. The results are also interpreted in the context of Type-I and Type-II two-Higgs-doublet models.