  The importance of the H -> ZZ -> 4l "golden" channel was shown by its major
role in the discovery, by the ATLAS and CMS collaborations, of a Higgs-like
boson with mass near 125 GeV. We analyze the discrimination power of the matrix
element method both for separating the signal from the irreducible ZZ
background and for distinguishing various spin and parity hypotheses describing
a signal in this channel. We show that the proper treatment of interference
effects associated with permutations of identical leptons in the four electron
and four muon final states plays an important role in achieving the best
sensitivity in measuring the properties of the newly discovered boson. We
provide a code, MEKD, that calculates kinematic discriminants based on the full
leading order matrix elements and which will aid experimentalists and
phenomenologists in their continuing studies of the H -> ZZ -> 4l channel.
