Physics: Building for discovery in the global context

Jim Siegrist, Associate Director for High Energy Physics at the Office of Science, U.S. Department of Energy details how the organisation is building for discovery, using the excellent example of their High Energy Physics program

The pursuit of science drives innovation. Big questions attract bright minds and these dedicated scientists and engineers solves big problems. Discovering the nature of our universe for instance, demands experiments that operate in the extremes, from ultra-sensitive deep underground detectors to space-based experiments and the largest machine ever constructed, the Large Hadron Collider.

Delivering scientific discoveries that advance human knowledge requires pushing the frontiers of technology. The new tools that are developed, in turn, impact energy, the economy and national security. This engine of innovation is the core mission of the U.S. Department of Energy’s (DOE) Office of Science. As the largest federal sponsor of basic research in the physical sciences in the United States, the DOE Office of Science supports scientists and engineers at hundreds of institutions across the country and stewards ten national laboratories that host tens of thousands of users each year across their facilities.

DOE user facilities provide some of the most advanced tools of modern science, including the world’s fastest supercomputer, facilities for studying the nanoworld, the environment and the atmosphere, as well as world-class light sources, neutron sources, particle accelerators and colliders. These facilities are available to all users, without regard to nationality or institution, based on the scientific merit of the proposed work. Use of the facilities is also free for research intended to be published in the open literature. This strategy aims to enable scientists to use the best possible resources in their pursuit of discovery. To keep advancing our science program, the Office of Science is continually investing in this infrastructure and building for discovery.

For example, the High Energy Physics program, which seeks to understand how the universe works at its most fundamental level, is bringing together scientists from around the globe the create a U.S.-hosted world-class facility to study the science of neutrinos. There are three known types of neutrino but these ghostly neutral particles, a million times lighter than an electron, change their type as they travel from one point to another. The first clue to this puzzling behaviour was observed fifty years ago by Ray Davis, Jr., whose Nobel Prize-winning work found fewer neutrinos than expected from the sun in a detector in the Homestake Mine, a mile underground in the Black Hills of South Dakota.

Now we are returning to the same mine to host the international Deep Underground Neutrino Experiment, which will precisely measure this oscillation of neutrino types while aiming to measure any difference between the matter and antimatter versions of neutrinos. Over a thousand scientists from around the world are collaborating to build this experiment and their work may help us understand why the universe today is made of matter instead of antimatter. Eight hundred miles away, the Long-Baseline Neutrino Facility under construction at Fermi National Accelerator Laboratory will support this experiment by sending the world’s most intense neutrino beam directly through the earth between Illinois and South Dakota. We’re also working with international partners on a new linear accelerator that will power the Fermilab Accelerator Complex, serving this and future world-leading experiments.

Our scientists and engineers also apply their expertise to international experiments and facilities hosted elsewhere. Our long and successful partnership with CERN began with agreements signed in 1997, enabling U.S. scientists to provide important accelerator and particle detector components to the Large Hadron Collider programme. The Large Hadron Collider provides the only way for particle physicists to create and study the Higgs boson, which was discovered in 2012 and led to the 2013 Nobel Prize in Physics for its role in revealing the origin of mass of subatomic particles. The new bilateral U.S.-CERN agreement signed in 2015 enables over a thousand U.S. scientists to continue their collaborative research at the world’s highest energy particle collider, while developing and building accelerator and detector components for the future High-Luminosity Large Hadron Collider programme.

In Chile, the construction of the Large Synoptic Survey Telescope is underway in order to perform a ten-year optical imaging sky survey of nearly forty billion stars and galaxies in the southern hemisphere. The unprecedented amount of data it will provide will enable scientists to probe the nature of dark energy, which is accelerating the expansion of the universe. The National Science Foundation (NSF) leads LSST and the DOE Office of Science is contributing the largest digital camera ever constructed, with over three billion pixels, to record high- quality images with minimal downtime. In parallel, DOE is building the Dark Energy Spectroscopic Instrument, which DOE will operate on NSF’s Mayall Telescope in Arizona. It will provide complementary optical spectra of tens of millions of galaxies, enabling scientists to build a three-dimensional map of the nearby universe to shed light on dark energy. LSST and DESI will make their data publicly available after a proprietary period.

A suite of experiments are exploring the nature of dark matter, which accounts for five times as much of the universe as all ordinary matter combined. Dark matter could be created and detected using beams of particles from accelerators, such as the Large Hadron Collider or a number of DOE national laboratory facilities. Ultra-sensitive detectors deep underground are searching for signs of galactic dark matter as it passes through the earth. Our investments in technology development are also creating new types of detectors based on quantum sensors, which may find an early application in searches for ultralight dark matter particles that were previously thought inaccessible to experiment.

The DOE Office of Science invests in the future. The technology our scientists and engineers develop not only enables advances in science but impacts medicine, industry and national security. Our user facilities provide advanced tools that enable scientific discovery. We work with partners around the globe to create truly world-leading instruments to tackle some of the biggest questions in science. By providing enticing scientific challenges and offering world-class facilities that can help meet those challenges, the U.S. Department of Energy attracts the next generation of innovators to our programs and trains them to be the leaders of tomorrow.


Jim Siegrist

Associate Director for High Energy Physics

Office of Science, U.S. Department of Energy



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