Search for the Standard Model Higgs Boson at CMS in the 4-lepton channel

One of the main targets of the CMS experiment is to search for the Standard Model Higgs boson. The 4-lepton channel (from the Higgs decay h ?? ZZ*??4l, l = e,mu) is one of the most promising. The analysis is based on the identification of two opposite-sign, same-flavor lepton pairs: leptons are required to be isolated and to come from the same primary vertex. The Higgs would be statistically revealed by the presence of a resonance peak in the 4-lepton invariant mass distribution. The Higgs mass is a free parameter of the Standard Model, and the 4-lepton channel search is sensitive almost in all mass range. With data collected in 2010 and 2011 (4.7 fb-1 at ??s = 7 TeV) the Higgs has been excluded in a wide region of mass at 95% of confidence level. The 4-lepton analysis will be presented, spanning on its most important aspects: lepton identification, variables of isolation, impact parameter, kinematics, event selection, background control and statistical analysis with data-MC comparison.