Two Z particles together for the first time at CERN

29 October 1997  

Two Z particles together for the first time at CERN Display the high resolution version


Two Z particles die together instants after their simultaneous production at the Large Electron Positron Collider (LEP) at CERN, the European Laboratory for Particle Physics. One Z has decayed into a quark and an antiquark, which shoot off back-to-back and create opposite "jets" of particles, shown by the sprays of green and red tracks. The yellow tracks reveal the paths of a muon ("heavy electron") and its antiparticle; these are the decay products of the other Z. This autumn LEP has been running at higher energies than ever before - sufficient to produce pairs of the heavy Z particles, in just the way they would have formed in the initial aftermath of the Big Bang. This image is from the DELPHI experiment, one of four experiments that study collisions at LEP between matter (electrons) and antimatter (positrons).

(The LEP collider and its experiments were shut down to make way for a new machine, the LHC, in November 2000.)

Credit: CERN / DELPHI

Please contact person or institution named for information about permission for public or commercial use.