In this page we have selected pictures of several basic types of Z decay events. The displays are X-Y projections, i.e. you look at them parallel to the beam axis. The central part of ALEPH consists of several different tracking detectors. The points where charged particles interact with the tracking detectors (hits) are shown as squares and the tracks fitted to the hits are drawn as thin lines. The outer part of ALEPH consists of calorimeters, i.e. detector components that measure the energy of the particles. The total energy deposited per calorimeter cell is drawn as a histogram. For penetrating particles (muons) one can see the hits in tracking chambers of the outermost calorimeter (hadron calorimeter) and muon detectors. There are also some blue hits. These originate from particles for which the trajectory does not point back to the vertex or which have low momentum.
For each event there is a choice from two colour sets.
The LEP running at the Z peak came to an end in September 1995. The first events at higher energies were announced in on 6th November 1995 in CERN Press Release PR 09.95
We give here a selection of the first events observed in Aleph at 130 GeV, 140 GeV and 161 GeV
You can search the full list of available DALI pictures using the picture database query form (you also can save or print these pictures).
firstname.lastname@example.org, 9th July 1996