Search for the Standard Model Higgs boson in the $H\rightarrow ZZ^{(∗)}\rightarrow 4\ell$ decay channel with the ATLAS detector

The search for the Standard Model Higgs boson in the decay channel $H\rightarrow ZZ^{(*)}\rightarrow \ell^+\ell^-\ell^{'+}\ell^{'-}$, where $\ell,\ell^{'}=e$ or $\mu$, is presented using 4.8 ${\rm fb}^{-1}$ and 5.8 ${\rm fb}^{-1}$ of proton-proton collision data at centre-of-mass energies of $7\:{\rm TeV}$ and $8\:{\rm TeV}$, respectively, recorded with the ATLAS detector at the Large Hadron Collider. The search is performed for Higgs boson masses between 110 and $600\:{\rm GeV}$. The Standard Model Higgs boson is excluded at 95% confidence level in the mass ranges $131\!-\!162\:{\rm GeV}$ and $170\!-\!460\:{\rm GeV}$, while the expected exclusion ranges are $124\!-\!164\:{\rm GeV}$ and $176\!-\!500\:{\rm GeV}$. An excess of events is observed around $m_{H} = 125\:{\rm GeV}$, with a local significance of 3.4 standard deviations.