Events in Delphi

Who dunnit? 4

This looks like muon tracks, as there are single tracks and no energy in the electron-photon detector (red ring). But notice - the tracks do not go through the centre of the detector! This is in fact a track due to a cosmic-ray muon, which has travelled through the detector from top to bottom.

By contrast, this shows a muon and an antimuon made in a collision. Here the particles moved off back-to-back from the centre, where the electron-positron collisions occur.

c.sutton 26/9/97