The Nuclear Science Advisory Committee announces the release of 'The 2023 Long Range Plan for Nuclear Science'

The Nuclear Science Advisory Committee (NSAC) has announced the release of a comprehensive report summarizing anticipated directions in nuclear physics. "The 2023 Long Range Plan for Nuclear Science" underlines the priorities of U.S. researchers in nuclear physics and will be used to summarize recent progress, identify important scientific topics, and identify opportunities for the coming decade. Illinois physicists have played key roles in the report’s publication by serving as organizers, collecting report contributions, and writing white papers.

 

This report is the eighth in a series commissioned by the NSAC, a group tasked with advising the U.S. Department of Energy (DOE) and the National Science Foundation (NSF) on research priorities in fundamental nuclear science. The report serves as a guiding document for stakeholders, including government agencies, research institutions, and the broader scientific community, to align their efforts and investment in nuclear physics with the priorities identified through this community-driven process, a tradition started in 1979.

 

Illinois Physics Professor Anne Sickles comments, “The overarching goal is to provide a document accessible to policymakers about what the interesting questions in nuclear physics are and what the field sees as the goals for the next several years.”

 

Current research efforts across the field of nuclear physics fall under three main categories: nuclear structure and reactions, quantum chromodynamics (QCD), and fundamental symmetries. Scientists studying nuclear structure investigate the interiors of atomic nuclei and the formation of isotopes through astro-nuclear processes. QCD is the study of the strong force, a fundamental force holding certain elementary particles together to form larger ones such as the proton and neutron. And the field of fundamental symmetries searches for violations of certain rules that could reveal new insights about fundamental physical laws.

 

The report outlines priorities along these three axes. Nuclear physicists at Illinois are heavily invested in both QCD and fundamental symmetries.

 

On the QCD frontier, the report contains funding recommendations for a number of existing facilities, including the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory and the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson National Laboratory. Recommendations are also made for the planned Electron-Ion Collider as well as for continued American participation at CERN’s Large Hadron Collider (LHC) near Geneva, Switzerland.

 

Sickles’ research focuses on so-called “hot” QCD—the study of nuclear constituents called quarks and gluons at extremely high temperatures. Increased funding in this area would allow Sickles to lead an experiment at the RHIC’s sPHENIX, a detector for a state of matter known as the quark-gluon plasma. Supporting data-taking and analysis using the newly constructed sPHENIX detector was identified as a high priority in the last long-range plan in 2015.

 

Sickles says, “We're trying to understand the emergent properties of strongly interacting particles when they’re very close together at very high temperatures. We started taking data in May 2023, and potential funding from future grants will enable continued data-taking at sPHENIX as well as at the LHC over the next several years.”

 

In the field of fundamental symmetries, one big mystery is why the universe is dominated by “normal”—or baryonic—matter rather than antimatter. A major funding recommendation in the report is for experimental searches for a hypothesized process called neutrinoless double beta decay, which could help scientists explain the baryonic imbalance.

 

Illinois Physics Professor Chen-Yu Liu explains, “Most of the visible mass in the universe is made of baryons. We need to understand why this is the case, because even though the early universe had no baryons, our present-day universe is baryon-rich.

 

“In neutrinoless double beta decay, two nucleons emit two electrons and no neutrinos. If this process is confirmed, baryon number could be violated, partially explaining the asymmetry between baryonic matter and antimatter.”

 

In her research, Liu searches for evidence of CP-violation, another ingredient required for explaining the matter-antimatter imbalance. She makes exceptionally precise measurements of the neutron’s electric dipole moment’s value, which provides evidence of CP-violation. Additional funding would create opportunities for her to continue her work conducting ultracold neutron experiments at Los Alamos National Laboratory. Support is also essential to complete the construction of a parallel effort at Oak Ridge National Laboratory, led by Illinois Physics Professors Douglas Beck and Josh Long.

 

The report is a culmination of a year-long process. It represents a vision for the field of nuclear physics for the next 5 to 10 years. To create the report, community members called conveners organized town halls where they solicited input on the biggest open questions in nuclear physics. A writing committee then produced the final report based on this community input.

 

Faculty at Illinois Physics contributed at all stages in the development of the long-range plan, including writing the report, serving as conveners, authoring white papers, and presenting at town halls.

 

Towards the end of 2022, three major town halls were held, one for each of the three subdivisions in nuclear physics: Nuclear Structure, Reactions and Astrophysics (NSRA); Hot and Cold QCD; and Fundamental Symmetries, Neutrons and Neutrinos (FSNN).

 

Sickles, a co-convener of the QCD town hall, which met in September 2022, says, “We organized a program that included invited talks and open-mike sessions on both the big things coming up in QCD and what we've done over the last few years.

 

“We had town hall participants provide input on the wording of our recommendations through an anonymous survey, and later we did another survey on our proposed recommendations and got overwhelming support for them. This showed us that the QCD community is united in its goal to understand the strong force.

 

“In addition to recommendations for facility support, we prioritized diversifying and shoring up our workforce. This requires taking specific actions to develop a diverse and inclusive scientific workforce and devising appropriate codes of conduct.”

 

Once these town hall summaries were finalized, the writing committee synthesized them into a list of community-approved objectives deserving special attention from Congress. A week-long resolution meeting was held in July 2023 to discuss the details of the plan.

 

Liu is one of approximately 50 writing committee members. In this role, she helped to make critical decisions on what gets emphasized in the final recommendations.

 

Liu notes, “The principal role of the writing committee is to formulate a list of digestible recommendations to present to Congress. We have to really focus on goals we believe have the highest priority—goals supported not just by individual scientists or small groups but also by the community as a whole. We have to help Congress understand why it's important to support us in our research. We also emphasize that nuclear physics has a lot of societal benefits.”

 

To mark the report’s national launch, Illinois Physics will be hosting an event on Friday, October 6, from 1 to 2 p.m., in the Interaction Room of the Loomis Laboratory of Physics. The event will feature a webinar led by the NSAC Committee Chair Gail Dodge, who will give a summary presentation and answer questions. Discussions on the local impacts of the report will follow. All Illinois Physics faculty, staff, and students are welcome to attend.