Virginia Tech physicist earns Early Career Research award from Department of Energy

Marie Boër, assistant professor of physics in the College of Science, was recently selected as a recipient of the 2024 Early Career Research award by the U.S. Department of Energy. Funded by the Office of Nuclear Physics, the five-year, $875,000 grant will help fund Boër’s project to learn more about partons from an experimental and phenomenological point of view.

The Early Career Research Program began in 2010 to bolster the nation’s scientific workforce by supporting exceptional researchers at the outset of their careers, when many scientists do their most formative work. These awards are critical to Department of Energy’s longstanding efforts to develop the next generation of STEM leaders to solidify America’s role as the driver of science and innovation around the world.

Fundamental physics

While the field of nuclear physics focuses on an atom’s nucleus, which is composed of nucleons, or protons and neutrons, hadronic physics – Boër’s specialty – explores the structure of the composite particles that make up protons and neutrons. The two groups of composite particles, also known as partons, are quarks and gluons. Learning more about these particles is the objective of Boër’s research.

“Our goal is to understand the static and dynamic properties of the quarks when they are confined in a nucleon – trying to see their position distribution, their momentum distribution,” said Boër, who is also a bridged faculty member at the Jefferson Lab in Newport News. “We are trying to see how the properties at the level of the quarks will influence, for example, the properties that we observe at the level of the proton, such as its intrinsic spin.”

Since the discovery of quarks in the 1960s and gluons in the 1970s, theoretical models have been created to develop some understanding of these partons, yet there is potentially more to learn – just as the discovery of the contents of the nuclei in the last century led to the study of radioactivity.

“Our goal is to learn what ‘matter’ is, starting from its elementary constituents, the fundamental building blocks,” said Boër.

Learning "what is inside of inside of inside"

Boër’s interest in hadronic physics was indirectly sparked as a child by an “old guy” – a biochemist – who told her that there are things inside what you can see with the naked eye. For example, if you look at your finger, you can see some cells, but there are also things inside those cells that you can’t see.

“That would trigger my curiosity,” said Boër. “I always had this idea, I want to learn what is inside of inside of inside.”

While that curiosity initially led Boër to study chemistry, she realized she wanted to delve even deeper and began studying physics instead. She became specifically interested in hadronic physics, as she wanted to study the elementary bricks of matter — quarks and gluons — and the theory of strong interaction binding them all together.

When Boër, a native of France, came to the United States for her postdoctoral work, she began working on various topics in hadronic physics but had the opportunity to return to her research on 3D mapping of the nucleon as a member of Virginia Tech’s faculty. With the resources now afforded to her, the project she started in her spare time can be further developed.

Novel reactions lead to new discoveries

Boër’s grant-winning project, titled “Multi-channel Access to Generalized Parton Distributions,” will include several new and dedicated experiments that will be developed at the Jefferson Lab. Experimental data will be analyzed to expand global data accessing generalized parton distributions (GPDs), which contain the relationship between a parton’s longitudinal momentum and transverse position. Finally, multi-channel/multi-observable fits of functions of the GPDs will be produced.

What makes Boër’s approach unique is that the novel reactions measured in this research will access – for the first time – kinematics enabling a 3D interpretation, or tomography, of the quark and gluon distributions.

“The idea is that you will make a slice at high momentum – which is more likely to be quarks – a slice at intermediate momentum, all the way up to very low momentum, where you are more likely to have gluons,” said Boër. “Now if you put all these slices back together, you have a three-dimensional picture. That’s the same idea when you do an MRI for instance – you take slices of the body, you put them back together, and the doctor will have a three-dimensional idea of what is inside your body. That's the same thing we are doing with the protons.”

With these measurements, Boër and her team want to demonstrate whether GPDs are universal functions, a conclusion that would mark a milestone in the field of physics.

Another aspect of Boër’s project involves the development of a muon detector. While the current reactions used to study partons provide good information, they miss a significant piece of the puzzle when extended to a 3D model. Only one known reaction – a reaction that produces muons, which are heavy electrons – is able to fill in this missing information.

International impact

Not only is Boër’s project expected to generate new foundational knowledge in hadronic physics, but it also aims promises to grow support in the field, which is less well-known around the world.

International collaboration is a major component of this project, with groups in Armenia and France in particular working alongside other U.S. universities. Boër’s students bring their own international flair, with postdoctoral scholars from India and Turkey, two graduate students from Nigeria, and over 30 undergraduates from all over the world – hailing from every continent except Australia – working on this project.

“It would be a great achievement if we could develop long term relations with other countries – via student’s exchanges, for instance – who have not been historically involved in hadronic physics, and form more students in this field,” said Boër.