Z -> mu mu A Z particle can decay to a muon and an anti-muon. It is very difficult to find the muons in this display. Physicists do not rely solely on calorimeters for muon identification. Since the muons keep most of their energy as they go through the calorimeter, there are tracking chambers outside it where the muons leave a trace. Physicists match that trace with the calorimeter muon shower shape to confirm the presense of a muon. Watch this event rotate with an or .