Special Seminar -Chris Martin-Johns Hopkins University-What did we find? Characterizing a new particle using 4l events from the CMS Experiment.

A new resonance decaying to a pair of vector bosons was discovered in 2012 by the ATLAS and CMS experiments at the LHC. In the wake of this discovery a rush of measurements was made to characterize this discovery. The four-lepton final state has been instrumental in both the discovery and characterization of this new particle. With only about 20 events seen in the resonance peak at 125GeV the CMS experiment has been able to make considerable progress in characterizing the Higgs-like boson using the wealth of information in this final state in concert with other decay modes. Two recent results from the CMS experiment provided breakthroughs in the study of the Higgs-like boson properties. One is the measurement of the width from an interplay between the off-shell and on-shell production, setting a limit three orders of magnitude tighter than previous limits. The other is the tensor structure measurement of the bosons interactions with pairs of vector bosons, leading to constraints on its spin-parity properties, where only limited measurements had been done before. Both of these breakthroughs provide further conformation that CMS has discovered a Higgs boson near 125GeV.