a machine for forcing particles (= extremely small pieces of matter) to hit each other at high speed so scientists can study what is produced

Scientists at Cern in Geneva have switched off LEP, the large electron positron collider, after a fruitful 11-year run. 在成功运行11年后，日内瓦塞恩的科学家关闭了大型正负电子对撞机（LEP）。

Researchers observed a series of anomalous results on their giant Large Electron Positron (Lep) collider, a 16-mile underground atom smasher drilled underneath Geneva. 研究人员在体积庞大的大型正负电子（Lep）对撞机上观察到一系列反常结果，该对撞机是一个原子加速器，位于日内瓦地下16英里处。