On July 24, a National Academy of Sciences (NAS) committee issued a report of its findings and conclusions related to the science case for a future U.S.-based Electron-Ion Collider (EIC), a particle accelerator in which electrons collide with atomic nuclei.
Four University of California campuses (UC Riverside, UC Berkeley, UCLA, and UC Davis) and the three UC national laboratories (Los Alamos National Laboratory, Lawrence Berkeley National Laboratory, and Lawrence Livermore National Laboratory) have formed a coalition to build a significant portion of the EIC detector in California.
UCR physicists Kenneth Barish and Richard Seto are founding members of the Electron-Ion Collider Users Group (EICUG), comprised of about 700 physicists from 29 countries.
“This machine is the future of our field, and will become of focus of our research efforts,” said Barish, a professor of physics and the chair of the Department of Physics and Astronomy. “The EIC, a $1 billion US project, will revolutionize our understanding of the proton.”
The EIC is a specialized accelerator that, like a precise microscope, will allow the imaging of the proton and shed light on its constituents — quarks, anti-quarks and gluons. The fundamental building block of nature, the proton was formed a microsecond after the birth of the universe.
“The understanding of the confinement of the proton which result from these studies impacts our understanding of the evolution of the universe,” said Barish, the UCR representative for the EICUG.
The U.S. Department of Energy asked the National Academies of Sciences, Engineering, and Medicine to form a committee to carry out an assessment of the scientific justification for a U.S. domestic electron ion collider facility.
“The NAS commissioned an assessment of the scientific justification of such a collider,” Barish said. “The committee unanimously found that an EIC will address profound questions about the neutrons and protons and how they are assembled to form the nuclei of atoms. The committee further finds that an EIC will be a unique facility in the world and would maintain US leadership in nuclear physics. The Department of Energy is now expected to begin the funding process.”
Protons and neutrons make up about 99.9 percent of the mass of visible matter. Scientists are still learning about how their internal constituents combine to produce properties such as mass and spin. The role of quarks, antiquarks, and gluons in determining mass and spin is an unsolved mystery in physics. To solve this mystery, a new type of particle collider is needed.
The proposed EIC will allow collisions of very-high energy ion and electron beams, producing snapshots of the internal structure of protons and nuclei. What scientists learn about gluons and the “strong nuclear force” could potentially power the technologies of tomorrow.
This project will be funded primarily by the Department of Energy’s Office of Science, Office of Nuclear Physics, which will decide where an EIC would be built.
Physicists like Barish and Seto argue that building an EIC will maintain and expand U.S. leadership in nuclear physics and accelerator science—fields that impact health, national security, energy, and the development of computational tools for managing “big data” enterprises.
“The project will also serve as a training ground for hundreds of students,” Barish said.
-Iqbal Pittalwala