In focus US accelerator projects

Evolution, ambition, collaboration: these are the defining themes of this CERN Courier In Focus on large-scale accelerator projects in the US. Fermilab’s Proton Improvement Plan II, our cover theme, is an ambitious reimagining of its accelerator complex that, upon completion in 2028, will drive a diverse experimental programme in particle physics (p25). Elsewhere, the engagement of the international nuclear- physics community will be front-and-centre as the Electron–Ion Collider takes shape through the 2020s (p10). Meanwhile, the Facility for Rare Isotope Beams is about to open up new frontiers in the study of rare isotopes (p5); SLAC’s LCLS-II upgrade will take X-ray science to the next level (p20); and Berkeley Lab’s pioneering Cyclotron Road innovation initiative opens for applications (p34). These and other projects, such as the Proton Power Upgrade at ORNL’s Spallation Neutron Source, demonstrate the continuing importance of accelerators for fundamental and applied research. That reference point, in turn, will inform the Particle Physics Community Planning Exercise (“Snowmass 2021”) as it gets underway this autumn, identifying a vision for the future of particle physics in the US and its international partners for the next 10 years and beyond.