CERN to develop plans for new circular collider

Science : CERN’s 27-km-circumference Large Hadron Collider (LHC) is planned to run until 2030. Since before construction even began on the LHC, it was generally assumed by particle physicists that it would eventually be replaced by a 30-km-long linear collider, for which there are two proposed designs. However, CERN has now announced that it will instead develop a pair of plans for a circular collider with a circumference of 80 to 100 km. The plans call for two colliders to be built, one after the other. They will use the same tunnel, with the first collider being replaced after 20–30 years with the second, much more powerful collider. The goal is to have the plans ready for the next revision of Europe’s particle-physics strategy in 5 years. The dual-use approach mirrors the plan that led to the construction of the LHC, which reused a tunnel built in the 1980s for a less powerful collider. It is likely that the final decision on whether to go with one of the already-existing linear collider plans or the new circular collider will depend on further results from the LHC.