The first peak you see (in the Special Relativistic mass distribution) is the J/Psi resonance, which is composed of a charm and anti-charm quark. It was discovered in 1974 at SLAC and Brookhaven National Lab almost simultaneously!
The second peak is the Upsilon resonance, which is composed of a bottom and an anti-bottom (or beauty and anti-beauty, if you prefer) quark. It was discovered in 1979 at Fermilab.
If you wait long enough for the events to accumulate in the animation, you will see a peak start to form at around 90 GeV/c^2. This is the Z boson and was predicted in 1968, but was not observed until 1983 at CERN.