Background Estimation for the Search of the Standard Model Higgs Boson in the Decay Channel $H \to ZZ* \to 4\ell$ with the CMS Experiment at $\sqrt s$ =7 TeV and 8 TeV

The estimation of background processes contributing in the H → ZZ* → 4l decay channel has been reported, with each Z boson decaying to an electron or a muon pair. The analysis uses pp collision data recorded by the CMS detector at the LHC, corresponding to integrated luminosities of 5.1 fb-1 and 12.2 fb-1 at centre-of-mass energies 7 TeV (2011) and 8 TeV (2012). The results contributed in the observation of an excess of events at a mass near 126 GeV with a local significance above the expected background of 4.5 standard deviations and ZZ cross-section measurement at centre-of-mass energies equal to 7 TeV and 8 TeV.