Next Decade Ground: The CMB-S4 Experiment

CMB-S4 is a next-generation ground-based cosmic microwave background (CMB) experiment consisting of dedicated telescopes equipped with highly sensitive superconducting cameras operating at multiple sites. CMB-S4 will provide a dramatic leap forward in our understanding of the fundamental nature of space and time and the evolution of the Universe. The science goals of CMB-S4 include illuminating cosmic inflation, measuring the sum of neutrino masses, searching for relativistic relics in the early universe, characterizing dark energy and dark matter, and mapping the matter distribution in the universe. These goals require measurements with unprecedented sensitivity and control of systematic errors. To address this challenge, the CMB community has come together to advocate a single comprehensive “Stage-4” experiment, called CMB-S4, which has been endorsed by the 2014 report of the Particle Physics Project Prioritization Panel (P5) “Building for Discovery,” and the 2015 NAS/NRC report “A Strategic Vision for NSF Investments in Antarctic and Southern Ocean Research.”