Now, her work to reveal the nature of matter at the U.S. Department of Energy's Thomas Jefferson National Accelerator Facility has just won special recognition: the prestigious 2024 Guido Altarelli Award – Experimental Physics. The award was presented to Szumila-Vance “for her outstanding contributions to investigations of color transparency and other nuclear manifestations of QCD.”
The 2024 Guido Altarelli Award – Theory was presented to Javier Mazzitelli, Paul Scherrer Institut (PSI), “for his outstanding contributions to precision calculations in Higgs boson and top quark production at the LHC.” Both awardees received the award at DIS2024: 31st International Workshop on Deep-Inelastic Scattering and Related Subjects in Grenoble, France in April.
The honor is given to junior scientists for outstanding contributions to high-energy and nuclear physics. It’s named for the late Guido Altarelli, a founding father of quantum chromodynamics, or QCD, and a strong supporter of early-career physicists.
Szumila-Vance is quick to share the credit for her award with her Jefferson Lab colleagues.
“I’m just really honored and humbled, and I feel like I’ve gotten to work with a lot of really great physicists here at the lab,” she said. “I feel like in some way it expresses a lot of the work that we all do together.”
On the hunt
The work that earned her plaudits from the senior experimental and theoretical particle physicists who comprise the award selection committee centers on the hunt for elusive “squeezed protons.”
Every nucleus contains protons. An ordinary proton consists of three quarks bound by the strong force, also called the color force. QCD is the theory that describes how quarks and the color force interact.
Ordinarily, the color force is so strong that it leaks out of the proton, binding it to other protons and neutrons in the nucleus.
But QCD predicts that the proton can be squeezed in such a way that the quarks clump together so tightly in the color force that it no longer leaks out, leaving the proton to move freely and escape the nucleus.
This phenomenon is known as “color transparency,” since the proton has essentially become invisible to the color force of surrounding particles. It’s also a fundamental prediction of quantum chromodynamics.
Earlier experiments have observed indications of color transparency in simpler two-quark systems in the pion and rho-mesons; further motivating the search for such an effect in three-quark protons.
The recent experiment that aimed to observe color transparent protons needed the highest beam energy available at Jefferson Lab and required the commissioning and successful running of a brand-new spectrometer that could measure knocked out protons to such high momenta. Szumila-Vance played a crucial role in the commissioning of the new Super High Momentum Spectrometer which continues to serve other experiments in Hall C.
Despite measuring knocked out protons to the highest momenta, the most recent experimental effort did not observe color transparent protons, thereby placing strong limits on theoretical descriptions of protons.
“We haven’t been able to directly measure it yet or to observe it,” Szumila-Vance said. “Which is interesting, too, because it tells us that the proton and the picture of how we describe it may be more complicated than we thought.”
Upon receiving the Altarelli Award, she presented her work in a presentation called “Chasing QCD Signatures in Nuclei.”
Now, scientists will push the observations of color transparency to new limits. With her collaborators, Szumila-Vance will extend the measurements on the pion hoping to observe the full effect of squeezing the two-quark system. She is also leading a new experimental effort to search for color transparent protons in new dynamics in smaller nuclei.
“Theorists can better calculate what’s happening inside smaller nuclei, and we can compare directly to calculations a little better,” Szumila-Vance said.
“What’s exciting is that we’re learning something that is new. We’re doing something that’s never been done before,” she said.
“So, we’re furthering the knowledge of everybody of how we understand the nucleus and how it’s bound together. I think it’s pretty amazing to be able to do something for your job that furthers humankind’s understanding of something.”
When she is not studying color transparency, Szumila-Vance pushes new experimental boundaries with her colleagues in the commissioning and running of large area gaseous electron multiplier (GEM) tracking detectors at the highest rates to better understand the internal distributions and descriptions of protons and neutrons.
Life lessons
Szumila-Vance studied aerospace engineering and space physics at Embry-Riddle Aeronautical University in Prescott, Arizona.
After earning her undergraduate degrees, she served in the U.S. Army National Guard as an aeromedical evacuation pilot and medevac platoon leader, deploying to Afghanistan’s Helmand Province.
She says the experiences there also proved invaluable to her work in experimental nuclear physics, especially in “how to work together as a team, because at Jefferson Lab, we perform experiments on a very big scale that takes teamwork to make things happen.”
In 2014, Szumila-Vance earned her master’s degree and in 2017 her doctorate in physics from Old Dominion University in Norfolk. From 2017-2019, she was a postdoctoral fellow at Jefferson Lab, and from 2019-2020 a postdoctoral fellow at MIT/George Washington University.
In 2020, she joined Jefferson Lab as a staff scientist.
Further Reading
Guido Altarelli Award
Nuclear Physicists on the Hunt for Squeezed Protons
Bite-Size Science: What’s Going On in the Proton
Salute to Veterans with Holly Szumila-Vance, U.S. Army
By Tamara Dietrich
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DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.
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