Increasing LEP's energy from 90 to 140 GeV

LEP's year was dominated by preparations for its energy upgrade from LEP1 to LEP2. A new way of operating the machine was mastered, and new accelerating cavities were installed. In December 1995, LEP took its first step toward LEP2, with an increase of energy from 90 to 140 GeV, and earning the label LEP 1.5. The reconfigured machine worked straight away, and the experiments produced new results soon after. ALEPH, one of the LEP experiments, found some unexpected results which appeared difficult to understand on the basis of known physics. Read more.