Large electron-positron collider

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The Large Electron-Positron Collider ( LEP , German name Large Electron-Positron Storage Ring ) was a particle accelerator at the European Nuclear Research Center CERN near Geneva .

It was in operation from 1989 to 2000 and served as a collider for electrons and positrons with center of gravity energies of up to 209  GeV in the last expansion stage LEP2 (see also colliding beam experiment ). The first particle collisions were detected on August 13, 1989. Four large experiments were in operation at the LEP: ALEPH , Delphi, L3 and OPAL , which in the eleven years of operation have yielded some important scientific findings: They were used to determine the exact mass of the W and Z bosons and to prove that exactly three light ones Types of neutrinos exist.

The LEP had a circumference of 27 kilometers and was between 50 and 175 meters below the surface of the earth in a tunnel on the border between Switzerland and France. The tunnel was rebuilt in order to be able to operate the successor to the LEP, the Large Hadron Collider , from 2008 . On September 10, 2008, the new plant went into operation.


Web links

Commons : Large Electron – Positron Collider  - collection of images, videos and audio files

Individual evidence

  1. CERN : Celebrating 30 years of a giant LEP for humankind , August 13, 2019
  2. DELPHI experiment
  3. ^ The L3 Experiment at CERN
  4. Particle Data Group , see mass data for W and Z bosons.
  5. Particle Data Group, Number of Light Neutrinos PDF
  6. ^ LHC Machine Outreach