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Particle colliders that use elementary particles called muons could outperform conventional colliders, while requiring much smaller facilities. Muon cooling, a milestone on the road to these muon colliders, has now been achieved.
“SMASH! Colossal colliders are unlocking the secrets of the universe.” The cover story of the 16 April 1990 issue of Time magazine discussed giant particle accelerators, including the Superconducting Super Collider in Texas, which was ultimately judged to be too expensive for completion. Researchers at CERN, Europe’s particle-physics laboratory near Geneva, Switzerland, went on to construct the Large Hadron Collider (LHC) in an existing tunnel. The LHC and other accelerators have been responsible for many major discoveries, but these “colossal colliders” have become colossally costly. Innovative approaches will thus be required to reduce the expense of future colliders in the search for previously unseen particles and physics phenomena. In a paper in Nature, the Muon Ionization Cooling Experiment (MICE) collaboration1 reports results that bring scientists a step closer to realizing one of these innovative approaches: a muon collider.