FRIB physicist simulates beam dynamics for electron-ion colliders, supported by DOE-SC

The U.S. Department of Energy Office of Science (DOE-SC) Office of Nuclear Physics awarded a two-year grant to Dr. Yue Hao for his research on beam dynamics for electron-ion colliders (EICs).

Hao is an associate professor of physics at FRIB. Hao has a joint appointment in the MSU Department of Physics and Astronomy.

Hao will receive the $120,000-per-year grant for two years through the Office of Nuclear Physics for his project titled "Development and Test of Simulation Tools for EIC Beam-Beam Interaction.” Hao’s work will focus on theoretical models and computer simulations. His team will explore improving current accelerator designs.

All matter around us is made up of atoms, which are made up of even smaller fundamental particles called quarks and gluons. The former are point-like particles, while the latter act as the “glue” keeping everything from humans to planets together. Despite their importance, some fundamental questions regarding the gluons’ role in nuclei remain unanswered. The only way to answer them is with a powerful new EIC.

In the 2015 Long Range Plan for Nuclear Science, the U.S. Nuclear Science Advisory Committee recommended building a new high-energy EIC as the highest-priority new-facility construction following the completion of FRIB. Two facilities, the Thomas Jefferson National Accelerator Facility (Jefferson Lab) and Brookhaven National Laboratory, are developing facility concepts.

The EIC consists of two accelerators. One produces an intense beam of electrons, and the other a high-energy beam of protons or heavier atomic nuclei. Those beams are then steered into collision, during which the electrons scatter off of the quarks within the heavier nuclei, providing a powerful way to probe the internal structure of nuclei. The proposed world-unique EIC will, for the first time, enable scientists to study these gluons in nucleons and nuclei.

Quarks and gluons interact via the strong nuclear force, one of the fundamental forces in nature. It binds together the fundamental particles of matter to form larger particles. As scientists get ready for the next-generation high-luminosity EIC with a wide energy range to understand this mysterious force, some major design challenges need to be addressed.

Hao’s project focuses on solving the beam-beam interaction problem: in addition to interacting via the strong force, quarks and gluons undergo electric and magnetic interactions that are difficult to avoid. The unwanted effects pose a problem for scientists since they can affect the quality and the lifetime of the beam. They also limit the amount of amount of data scientists can get.

“The newly proposed EIC design will enhance the amount of data collected by at least a factor of 100 more than previous EICs,” explained Hao. “But first we have to understand the beam dynamics.”

Hao’s team will use high-performance computing resources to develop and test new computational capabilities and algorithms. Those will be added to the existing EIC beam simulation codes, addressing the most critical topics related to beam-beam interaction, such as crab-crossing effects. Crab-crossing is the intentional alignment of the colliding beams at the point of head-on collision until they overlap completely. “The goal is to implement this for the first time in EICs,” he said, “and this will directly affect the collision rate.”

At the completion of this project, researchers should have a clear understanding of how to countermeasure these beam-beam effects in future EIC designs and provide ways to minimize reductions in quality, lifetime, and particle-collision rates.