Search for a Standard Model Higgs boson produced in the decay channel 4l

A search for a Higgs boson in the decay channel ${\rm H} \rightarrow {\rm ZZ}^{(*)}$ with each Z boson decaying to an electron or muon pair is presented using pp collisions from the LHC at $\sqrt s$ = 7 TeV. The data analyzed correspond to an integrated luminosity of $1.13 \pm 0.07$~fb$^{-1}$ recorded by the CMS detector in 2010 and 2011. The search covers Higgs boson mass ($m_{\rm H}$) hypotheses of $110 < m_{\rm H} < 600 \GeVcc$ with an expected sensitivity varying between one and five times the standard model cross section at 95\% CL over most of the mass range. Fifteen events are observed, while $14.4 \pm 0.6$ events are expected from standard model background processes. Six of the events are below the kinematic threshold of two on-shell Z's ($m_{\rm H} < 180 \GeVcc$), while $1.9\pm 0.1$ background events are expected. The probability that the background fluctuates to the observed number of events is 1.3\%. The events are not clustered in mass excluding interpretation as the standard model Higgs boson. The distribution of events is consistent with the expectation of standard model continuum production of ${\rm ZZ}^{(*)}$ pairs and the production cross section for $60 < m_{\rm Z} < 120 \GeVcc$ is measured to be in agreement with the predicted value. Upper limits at 95\% CL on the cross section$\times$branching ratio for a Higgs boson with standard model-like decays exclude cross sections from about one to two times the expected standard model cross section for masses in the range $180 < m_{\rm H} < 420 \GeVcc$. Reinterpreted in the context of the standard model with four fermion families a Higgs boson with a mass in the range 138 -162 $\GeVcc$ and 178-502 $\GeVcc$ is excluded at 95\% CL.