Tauon/antitauon events
Tauons and Antitauons decay very quickly after their production in the detector, so to sort them we need to consider their decay products.
Tauons either decay into light leptons, so either electrons or muons and three neutrinos or into one to three light quarks and one neutrino. Neutrinos leave the detector undetected and will carry some of the energy away.
Therefore tauon/antitauon events usually have two or three tracks in the detector. However sometimes one particle gets lost, so that only tree tracks are visible.
In the case of two tracks one distinguish tauon/antitauon events from electron/positron or muon/antimuon events if there’s only one clear muon track (i.e. a track with lots of green hits along their outer tracks). A single muon can only come from a tau-process, since all particles are always produced in pairs.
It becomes more tricky, if both or none or the tauons decay into muons, so that the events looks at first glance like a e+e− or 𝛍+𝛍− event. In that case one can use, that 𝛕+𝛕− decays also produce many neutrinos, which the detector cannot see. As a result, 𝛕+𝛕− events usually have lots of missing energy.
Events with three or four tracks are usually 𝛕+𝛕− or light quark events. To differentiate the two one can once again use the high missing energy in 𝛕+𝛕− events. Additionally 𝛕+𝛕− events are usually straighter. Sometimes one can also use, that tauons characteristically decay visibly into a single plus three tracks.
Example videos:
Example 1: Tauon/Antitauon Event
Bild © Teilchenwelt Bonn / YouTube
Example 2: Tauon/Antitauon Event
Bild © Teilchenwelt Bonn / YouTube
Example 3: Tauon/Antitauon Event
Bild © Teilchenwelt Bonn / YouTube