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Swiss President to visit CERN

Geneva, 23 May 2003. Pascal Couchepin, President of the Swiss Confederation, will visit CERN1 on 4 June to participate in the official inauguration of the underground cavern for the laboratory's ATLAS experiment. As the first new experimental cavern to be handed over to CERN by civil engineering contractors, this represents an important milestone for the Laboratory.

CERN is currently building a new particle accelerator, the Large Hadron Collider (LHC). Measuring 27km in circumference, the LHC will be the world's largest and most complex scientific instrument when it switches on in 2007. ATLAS, one of several experiments in preparation for the LHC, will study proton-proton collisions produced by the new accelerator to investigate some of the mysteries of our universe.

The ATLAS particle detector, 44 metres long and 22 metres high, is being built by an international collaboration of around 2000 scientists from 150 institutions in 34 countries around the world. The hand-over of the cavern signals the start of installation for this enormous device.

By detecting the particles produced in around 800 million proton-proton collisions per second, the detector will allow physicists to complete a journey that started with Newton's description of gravity. Gravity acts on mass, but so far science is unable to explain why the fundamental particles have the masses they have. Experiments at the LHC should give us the answer. LHC experiments will also probe the mysterious missing mass and energy of the universe – visible matter accounts for just 5% of what we know must exist. They will investigate the reason for nature's preference for matter over antimatter, and they will probe matter as it existed at the very beginning of time.

The hand-over ceremony will take place in the evening of 4 June. Speeches will be given by CERN Director General Luciano Maiani, President of CERN Council Maurice Bourquin, Arturo Henniger, speaking on behalf of the civil engineering consortium, ATLAS collaboration spokesman, Peter Jenni, and President Couchepin. The President will also visit the cavern 90 metres underground, and tour preparations for the experiments ATLAS, CMS and LHCb.

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, the Slovak Republic, Spain, Sweden, Switzerland and the United Kingdom. India, Israel, Japan, the Russian Federation, the United States of America, Turkey, the European Commission and UNESCO have observer status.