Finding the mass of the Higgs from its Decay Products

When one thinks of a decay such as H → Z + Z^* → e⁺ + e^- + µ⁺ + µ^-, the four possible combinations shown in the figure could come from Higgs decay or from background processes, so we need to look at a mass histogram plot of the combined mass of the four particles, in any of the combinations:

A mass histogram means that we look at a large number of events and plot the number of times each value of the total invariant mass occurs. It looks like a bar chart because the invariant mass values are divided into bins. The height of each bin represents the number of events for which the invariant mass falls into that range.

We are imagining that these come from these decays of a Higgs boson...

...but see the next page.