Easy to Detect when Higgs decays to Z + Z

Z bosons also have several decay modes, including Z → e⁺ + e^- and Z → µ⁺ + µ^-

The Z + Z decay mode is quite easy for the ATLAS and CMS experiments to detect when both the Z bosons decay into one of these two modes (Z → e⁺ e^- or Z → µ⁺ µ^- ). Then the four observed decay modes of the Higgs boson are:

The end result is that one will sometimes see (in addition to some unrelated particles) four muons, or, four electrons, or two muons and two electrons.