Evidence for a new state in the search for the standard model Higgs boson in the H to ZZ to 4 leptons channel in pp collisions at sqrt(s) = 7 and 8 TeV

A search for the Higgs boson in the H $\rightarrow$ ZZ four-lepton decay channel, with each Z boson decaying to an electron, a muon, or a tau pair, is reported. The search covers Higgs boson mass hypotheses in the range $110 < m_H < 600$ GeV. The analysis uses pp collision data recorded by the CMS detector at the LHC, corresponding to integrated luminosities of 5.05 ${\rm fb}^{-1}$ at $\sqrt{s}$ = 7 TeV and 5.26 ${\rm fb}^{-1}$ at $\sqrt{s}$ = 8\TeV. The four-lepton invariant-mass distributions for $m_{4\ell}$ and $m_{2\ell 2\tau}$ are found to be consistent with the standard model expectations for background ZZ production for invariant masses above 180 GeV. Upper limits at 95\% confidence level exclude the standard model Higgs boson in the range 131--162 and 172--525 GeV, while the expected exclusion range is 121--570 GeV. An excess of events is observed in the low $m_{4\ell}$ mass range, making the observed limits weaker than expected in the absence of a signal. These events cluster around a mass $m_{4\ell} \simeq 125.5$ GeV, giving rise to a local excess with respect to the background expectation, with a significance of $3.2\sigma$. This result constitutes evidence for a new massive state.