Search for a heavy Standard Model Higgs boson in the channel $H\to ZZ\to {\ell }^{+}{\ell }^{-}q\overline{q}$ using the ATLAS detector

Abstract

A search for a heavy Standard Model Higgs boson decaying via $H\to ZZ\to {\ell }^{+}{\ell }^{-}q\overline{q}$, where $\ell =e,\mu$, is presented. The search is performed using a data set of pp collisions at $\sqrt{s}=7\text{TeV}$, corresponding to an integrated luminosity of 1.04 fb⁻¹ collected in 2011 by the ATLAS detector at the CERN LHC collider. No significant excess of events above the estimated background is found. Upper limits at 95% confidence level on the production cross section (relative to that expected from the Standard Model) of a Higgs boson with a mass in the range between 200 and $600\text{GeV}$ are derived. Within this mass range, there is at present insufficient sensitivity to exclude a Standard Model Higgs boson. For a Higgs boson with a mass of $360\text{GeV}$, where the sensitivity is maximal, the observed and expected cross section upper limits are factors of 1.7 and 2.7, respectively, larger than the Standard Model prediction.