Proceedings of the 2021 US Community Study on
the Future of Particle Physics

(Snowmass 2021)

organized by the APS Division of Particles and Fields

These proceedings are dedicated to the memory of Meenakshi Narain (1964-2023),
in honor of her many contributions to Snowmass 2021.

The US Community Study on the Future of Particle Physics (Snowmass 2021) was a grassroots study to plan for US particle physics in the decade 2025-2035 with an eye towards the following decade. Snowmass 2021 was organized by the APS Division of Particles and Fields, with input and collaboration from the Divisions of the Physics of Beams, Astrophysics, Nuclear Physics, and Gravitational Physics. It began with a kick-off meeting at the 2020 APS April Meeting and a Community-wide Planning Meeting in October of 2020. Because of the COVID pandemic, the study was paused between January and September 2021. The study finally concluded at the Community Summer Study meeting at the University of Washington, July 17-26, 2022.

Snowmass 2021 was organized into ten working groups, or “Frontiers”: Accelerator (AF), Community Engagement (CEF), Computational (CompF), Cosmic (CF), Energy (EF), Instrumentation (IF), Neutrinos (NF), Rare Processes and Precision Measurements (RPF), Theory (TF), and Underground Facilities and Infrastructure (UF). These Frontiers comprise a broad array of ground-breaking research topics and the underlying technology and infrastructure to execute them. CEF explored how the U.S. HEP community can be more representative of and responsive to all of its members and can engage with society as a whole.

This web site presents the Proceedings of the study, at four levels of detail. First, there is an Executive Summary and a Summary chapter, presenting that main results of the study. Next, there is a summary report from each Frontier. Next, for each Frontier, there are Topical Group reports that discuss the relevant issues in more detail. There are also a number of commissioned cross-Frontier reports. Finally, there is the complete set of papers contributed to the study by members of the particle physics community. All of those documents can be found here through the links below. The Executive Summary and the Summary report can be found on the web page for Summary and Frontmatter. The Frontier report and the associated Topical Group reports can be found on that Frontier's web page. The cross-Frontier reports can be found on the pages for all of the relevant Frontiers. The contributed papers can be found on the page of the Frontiers to which they were sent, or on several pages for those papers that were cross-listed.

The Summary and Frontier Reports are also available as a 700-page book. This link will give you a pdf version of the Snowmass Book.

We hope that this compendium of reports will be a useful source of background material in planning the future of our field over the next decade.

                                                  - Editors of these pages: Joel N. Butler, R. Sekhar Chivukula, Michael E. Peskin