From the Director of Particle Physics and Astrophysics: Theory at SLAC: A Key Part of the High-energy Physics Program

August 12, 2011

In recent years I have been using the rubric of puzzle pieces to illustrate the interconnectivity of the high-energy physics program at SLAC. The pieces are accelerator-based particle physics, particle astrophysics and cosmology, underground physics, and accelerator R&D. These elements are connected by common underlying physics questions being addressed via complementary experimental approaches; common core technology capabilities; and the interplay of accelerator R&D and the demands of frontier science experiments. However, I realized in preparation for a recent comparative review of the HEP theory programs that this rubric has actually been missing two puzzle pieces that are essential to completing the analogy. The missing elements, which provide the intellectual foundation for the HEP program, are the particle physics and Kavli Institute for Particle Astrophysics and Cosmology theory groups.

Theory plays a central and essential role in high-energy physics. It helps to define the key questions and future directions of the field, and also guides the optimal scientific exploitation and interpretation of the data collected in experiments. The Department of Energy review of the HEP laboratory theory program on July 25–27 was an opportunity to showcase the vibrant and very productive HEP theory program at SLAC. The mission of the theory group is to pursue excellence across a broad spectrum of theoretical research in advancing the frontiers of particle physics, particle astrophysics and cosmology; to support and guide the strategic directions for the national and international particle physics and particle astrophysics experimental program; and to train and develop the next generation of theoretical physicists. By every measure the theory community at SLAC has performed superbly in advancing these three goals.

The SLAC theory community has produced well over 500 publications on a broad range of topics in just the last three years. These publications include seminal results on everything from formal field theory and string theory to phenomenology and model building to particle astrophysics and cosmology. Theory group members have been working closely with experimentalists at the Large Hadron Collider to define search strategies for new physics. As part of this work, they have been developing new, world-leading techniques for precisely calculating rare Standard Model processes with detector signatures similar to new physics. SLAC theorists have been advancing the physics case for an ultra-high-energy electron-positron collider and developing the arguments for a comprehensive computational cosmology program as the underpinnings of next-generation dark matter and dark energy experiments such as the Large Synoptic Survey Telescope and the Cryogenic Dark Matter Search. Close collaboration in understanding the gamma-ray universe as revealed by the Fermi Gamma-ray Space Telescope is also enabling rich scientific advances. Theory group members have assumed key national leadership positions in the field in helping define the future particle physics and astrophysics program. The list of past graduate students and postdoctoral research associates who have gone on to win appointments at many of the world’s leading universities is outstanding.

In its closeout comments, the review panel ranked the SLAC theory program very highly, seeing SLAC as one of the world’s great centers for theoretical research in particle physics, particle astrophysics and cosmology. It’s no secret that the theory group is the intellectual foundation of the SLAC HEP program and a major force nationally and internationally. Congratulations to JoAnne Hewett, Risa Wechsler and the theory groups on a very successful review!