V. High Energy Physics (HEP)

The mission of the High Energy Physics (HEP) program is to understand how our universe works at its most fundamental level. We do this by discovering the elementary constituents of matter and energy, probing the interactions between them, and exploring the basic nature of space and time.

Program Website:http://science.energy.gov/hep

The HEP program focuses on three scientific frontiers:

  • The Energy Frontier, where powerful accelerators are used to create new particles, reveal their interactions, and investigate fundamental forces;
  • The Intensity Frontier, where intense particle beams and highly sensitive detectors are used to pursue alternate pathways to investigate fundamental forces and particle interactions by studying events that occur rarely in nature; and
  • The Cosmic Frontier, where ground and space-based experiments and telescopes are used to make measurements that will offer new insight and information about the nature of dark matter and dark energy, to understand fundamental particle properties and discover new phenomena.

Together, these three interrelated and complementary discovery frontiers offer the opportunity to answer some of the most basic questions about the world around us.

  • Are there undiscovered principles of nature, such as new symmetries, or new physical laws?
  • How can we solve the mystery of dark energy?
  • Are there extra dimensions of space?
  • Do all the forces become one?
  • Why are there so many kinds of particles?
  • What is dark matter? How can we make it in the laboratory?
  • What are neutrinos telling us?
  • How did the universe come to be?
  • What happened to antimatter?

Because of the strong connections between the key questions, successfully addressing these questions requires coordinated initiatives at each of the frontiers. The HEP program invents new technologies to answer these questions and to meet the challenges of research at the frontiers. It supports theoretical and experimental studies by individual investigators and large collaborative teams—some who gather and analyze data from accelerator facilities in the U.S. and around the world and others who develop and deploy ultra-sensitive ground and space-based instruments to detect particles from space and observe astrophysical phenomena that advance our understanding of fundamental particle properties. There are three broad areas within the Office of High Energy Physics that support research and technology development aimed at these objectives:

(a) Experimental High Energy Physics Research

The experimental HEP research effort supports experiments utilizing man-made and naturally occurring particle sources to study fundamental particles and their interactions. Topics studied in the experimental research program include three major subprograms: proton accelerator-based research, electron accelerator-based research, and non-accelerator-based research.

The Proton Accelerator-Based research subprogram exploits major applications of proton accelerators: Energy Frontier investigations at the Large Hadron Collider at the European Organization for Nuclear Research (CERN), studying a wide variety of scientific issues, including new phenomena beyond the Standard Model, electroweak symmetry breaking, and quantum chromodynamics;  and an Intensity Frontier program utilizing the high-power proton beams at Fermilab, CERN and KEK (Japan) to produce intense secondary beams of neutrinos, kaons, muons, and other particles for experiments that probe the fundamental properties and interactions of these particles, particularly rare phenomena that can provide indications of new physics beyond the Standard Model.

The Electron Accelerator-Based research subprogram utilizes accelerators with high-intensity and ultra-precise electron beams to create and investigate matter at its most basic level. This includes Intensity Frontier research at the SLAC National Accelerator Laboratory (SLAC) and KEK “B-factories” probing the fundamental particle physics connected to the matter-antimatter asymmetry in the universe.

The Non-Accelerator Physics research subprogram explores those topics in particle physics that cannot be investigated with accelerators, or are best studied by other means. Scientists in this subprogram investigate topics such as dark matter, dark energy, neutrino properties, proton decay, the highest energy gamma rays, and primordial antimatter. Some of the non-accelerator particle sources used in this research are cosmic rays, neutrinos from commercial nuclear power reactors, the Sun, and galactic supernovae.

(b) Theoretical High Energy Physics Research

The theoretical HEP research subprogram provides the vision and mathematical framework for understanding and extending the knowledge of particles, forces, space-time, and the universe. Topics studied in the theoretical research program include, but are not limited to: phenomenological and theoretical studies that support the experimental research program, both in understanding the data and in finding new directions for experimental exploration; developing analytical and numerical computational techniques for these studies; and to find theoretical frameworks for understanding fundamental particles and forces at the deepest level possible.

(c) Advanced Technology Research and Development

The advanced technology R&D subprogram develops the next generation of particle accelerator and detector technologies for the future advancement of high-energy physics and other sciences, supporting world-leading research in the physics of particle beams and fundamental advances in particle detection. This subprogram supports long-range, exploratory research aimed at developing new concepts. Topics studied in the accelerator science program include, but are not limited to: analytic and computational techniques for modeling particle beams; novel acceleration concepts; muon colliders and neutrino factories; the science of high gradients in room-temperature accelerating cavities; high-brightness beam sources; and cutting-edge beam diagnostic techniques. Topics studied in the detector R&D program include, but are not limited to: low-mass, high channel density charged particle tracking detectors; high resolution, fast-readout calorimeters and particle identification detectors; improving the radiation tolerance of particle detectors; and advanced electronics and data acquisition systems. In addition, this program develops next-generation computational tools and techniques in support of the experimental and theoretical physics research programs.