These reports present the results of the 2013 Community Summer Study of the APS Division of Particles and Fields (Snowmass 2013) on the future program of particle physics in the U.S. Chapter 4, on the Cosmic Frontier, discusses the program of researc
h relevant to cosmology and the early universe. This area includes the study of dark matter and the search for its particle nature, the study of dark energy and inflation, and cosmic probes of fundamental symmetries.
