Gaining New Insights into Proton Structure

  • Headshot of Anselm Vossen

Anselm Vossen will take advantage of Jefferson Lab’s recently upgraded CEBAF Accelerator to learn more about the particles that build our universe.

The recent completion of the 12 GeV Upgrade of Jefferson Lab's Continuous Electron Beam Accelerator Facility has opened up a new realm for exploration of the particles and forces that give rise to our universe. Making the best of the opportunity to conduct groundbreaking research with a one-of-a-kind machine takes collaborations of the best and brightest minds in nuclear physics applying a bit of intellectual elbow grease to the design and analysis of experiments.

Anselm Vossen, a Jefferson Lab jointly appointed assistant professor at Duke University, has been awarded a DOE Early Career Award to develop experimental and analysis techniques that make full use of the new generation of high-precision experiments made possible by the upgrade of CEBAF.

“I am obviously quite happy to receive this award. It means that I have the security to plan my research for the next five years. It will also help me attract students and postdocs to my new group,” Vossen said. “I am especially glad to have received this award early in my tenure track position, which I started in January.”

Vossen’s research aims to gain insight into the proton structure in ways that can potentially reveal new information about Quantum Chromodynamics. QCD is the theory of the strong interaction – the force that governs how subatomic particles are made.

QCD provides an accurate description of the fundamental laws governing how the strong force binds particles called quarks together to make the more familiar protons and neutrons that are found in the nucleus of the atom. However, it doesn’t provide a comprehensive description of the dynamics that give rise to the observed properties of protons and neutrons.

For instance, the masses of the three quarks that make up a proton doesn’t add up to the proton’s mass, and while it’s accepted that the strong force itself likely contributes to the proton’s mass, it’s not clear how. This is one of the mysteries that Vossen hopes to address.

“I want to gain insight into the influence that the strong force fields inside the proton and neutron exert on the quarks as they move through the field,” Vossen explained.

He also plans to explore the dynamics of how the strong force binds quarks together to form new particles.

“Both of these questions are part of the puzzle we have to solve to understand how the dynamics of the strong force lead to the properties of protons and neutrons that make up the visible matter around us,” he said.

Vossen said his research will also further boost the experimental reach of data from CEBAF by combining it with data collected elsewhere, such as at the Belle II experiment located at the new SuperKEKB facility in Japan.

As a university-based researcher, Vossen will receive a DOE Early Career Award grant for at least $150,000 per year for the next five years for his project, titled “Novel Experimental Probes of Quantum Chromodynamics in Semi-Inclusive Deep-Inelastic Scattering and e+e- Annihilation.” Funds are used to cover salary and research expenses.

Contact: Kandice Carter, Jefferson Lab Communications Office, 757-269-7263,


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