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CERN celebrates LEP - the accelerator that changed the face of particle physics

Geneva, 9 October 2000. Members of government from around the world gathered at CERN1 on 9 October to celebrate the achievements of the Large Electron Positron collider (LEP), the Laboratory's flagship particle accelerator. Over the eleven years of its operational lifetime, LEP has not only added greatly to mankind's pool of knowledge about the Universe, but has also changed the way that particle physics research is done, and proved to be a valuable training ground for young professionals in many walks of life.

The celebration took place in one of the Laboratory's enormous experimental halls and the audience of scientists, politicians and scientists listened to speeches from:

Prof. Luciano Maiani, CERN's Director-General


Prof.Martinus Veltman, Nobel Prize Laureat 1999


Mr Adolf Ogi, President of the Swiss Confederation


Mr Roger-Gérard Schwartzenberg, Minister of Research


Mrs Edelgard Bulmahn, Minister of Education and Research


Lord Sainsbury of Turville, Minister of Science

United Kingdom

Prof. Ortensio Zecchino, Minister, University and Scientific and Technology Research


Mrs Anna Birules, Minister of Science and Technology


Prof. Andrzej Wiszniewski, Minister of Science


M. Lubomir Fogas, Deputy Prime Minister

Slovak Republic

Prof. Dimitar Dimitrov, Minister of Education and Science


Prof. Mariano Gago, Minister of Science and Technology


Mr Philippe Busquin, Commissioner for Research

European Union

The speakers praised CERN's important contribution to the advancing understanding of Nature's fundamental laws and also underlined the importance of basic research in promoting a healthy economic future.

The celebration closed with a performance of a ballet specially created by the world-famous choreographer, Maurice Béjart and performed by the Rudra-Béjart Dance School of Lausanne.

LEP's first beam circulated on 14 July 1989. One month later the first electron-positron collisions to produce Z particles were observed, and by the end of the year the four LEP experiments, ALEPH, DELPHI, L3, and OPAL had published their first results. Most profound among these is the discovery that nature has divided the fundamental particles into three distinct families. All of ordinary matter is made from particles of the lightest family. Why there are two heavier copies remains a mystery for tomorrow's physicists to solve. The LEP experiments went on to measure the properties of W and Z particles in excruciating detail. And as the accelerator nears the end of its career, hints of an exciting new era of physics have recently been seen. A theoretical framework to explain the range of fundamental particle masses has been proposed but not verified. Confirmation would come in the form of a new particle, the Higgs particle. All four LEP experiments have seen phenomena that could be explained by the production of Higgs particles, but these phenomena could also be due to known processes. Time alone will tell.

LEP's experimental collaborations range in size from some 300 to over 700 physicists from institutes around the world. This is collaboration on an unprecedented scale could only work through first class communication and it was this need that was the catalyst for the invention of the World Wide Web at CERN. The lessons of LEP are valuable stepping stones on the way to experiments preparing for LEP's successor, the Large Hadron Collider (LHC), which will come on stream in 2005. There the collaborations will number in the thousands. They have learned from the experience of LEP in managing global physics.

Over the lifetime of LEP, thousands of postgraduate students have passed through the experiments, learning the skills needed to work effectively in a high-tech multi-national environment. About half go on to pursue careers in particle physics research, but the rest are snapped up by the private sector in fields as diverse as computing, teaching, finance, as well as the high-tech industries that have been CERN's partners in the LEP adventure. As dignitaries from around the world converge on CERN to pay tribute to LEP, its experiments, and the people that made than happen, it is timely to reflect on how the flagship of CERN's research programme has helped to fashion a bright future for pure research on a global scale, and its partnership with society as a whole.


1. CERN, the European Organization for Nuclear Research, has its headquarters in Geneva. At present, its Member States are Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Israel, Japan, the Russian Federation, the United States of America, Turkey, the European Commission and Unesco have observer status.