Discovery of the W particle in the UA1 dete

Discovery of the W particle in the UA1 detector from the run of proton-antiproton collider producing high transverse energy electron (arrowed), October-December 1982. This particle is produced back-to-back with 'mising energy', indicative of the emision of an invisible neutrino. Detectors are devices which are used to measure the properties of particles. Some measure tracks left behind by particles and others measure energy. Founded in 1954, CERN is the world's leading particle physics research laboratory.