Figure 1 reports the upper plots
of figure 1 of the cited CDF paper.
The left side one shows the histogram of the
mass distribution in 8 GeV bins, for a total of about
(points with vertical bars).
The colored regions show the predictions
split into several contributions, the most important
of which is due to the production
of two W bosons, or of a W boson together with
a Z boson (red).
We see that at
around 140 GeV there are more events than
`expected' (an expression which we shall return to later).
CDF data before and after
`arithmetic' background subtraction
The right side plot shows the data after
the contributions called here `background'
(all but the red one of the left plot) were
subtracted `arithmetically'.5In the five bins between 120 and 160 GeV there are about
230 events (but in the side bins there are even
`negative events' whose meaning is only mathematical).
That was `the excess'.