Search for the Standard Model Higgs boson in the decay channel $H \rightarrow ZZ^{(*)} \rightarrow 4\ell$ with 4.8 fb$^{-1}$ of pp collisions at $\sqrt{s} = 7$ TeV

A search for the Standard Model Higgs boson in the decay channel $H\rightarrow ZZ^{(∗)}\rightarrow l+l−l'+l'−$, where $l,l' = e,\mu$, is presented. Proton-proton collision data at $\sqrt{s} = 7$ TeV recorded with the ATLAS detector and corresponding to an average integrated luminosity of 4.8 fb$^{−1}$ are compared to the Standard Model background expectations. Upper limits on the production cross section of a Standard Model Higgs boson with a mass between 110 GeV and 600 GeV are derived. The Standard Model Higgs boson is excluded at 95% confidence level in the mass ranges 135 GeV − 156 GeV, 181 GeV − 234 GeV and 255 GeV − 415 GeV. The largest deviations from the background expectation are observed for $m_{H}$ = 125 GeV with a $p_0$-value of 1.8%, $m_{H}$ = 244 GeV with a $p_0$-value of 1.1% and $m_{H}$ = 500 GeV with a $p_0$-value of 1.4%. Once the look-elsewhere effect is considered, none of these excesses is significant by itself.