Nuclear and Particle Physics

NSAC release of the 2023 Long Range Plan of Nuclear Science

On October 4^th, the U.S. Nuclear Science Advisory Committee (NSAC) announced the approval and release of A New Era of Discovery: The 2023 Long Range Plan for Nuclear Science.

NSAC release of the 2023 Long Range Plan of Nuclear Science

On October 4^th, the U.S. Nuclear Science Advisory Committee (NSAC) announced the approval and release of A New Era of Discovery: The 2023 Long Range Plan for Nuclear Science.

UVA Nuclear Physics faculty were heavily involved in the 2022-2023 Long Range Planning (LRP) process: Professor Zheng was a convenor of the Town Hall Meeting on Hot & Cold Quantum Chromodynamics (QCD), held at MIT in September 2022. Professor Paschke presented at the Fundamental Symmetries, Neutrons, and Neutrinos Town Meeting, held at UNC, Chapel Hill in December 2022; and Professors Počanić and Zheng are part of the writing committee that led the writing process of the final document. Many Nuclear Physics faculty also participated in the town meetings and/or contributed to the writing of the white papers as input to the process.

Many research projects of UVA's Nuclear Physics group were highlighted In the 2023 Long Range Plan. As usual, the long-standing pursuit of a full understanding of the nucleon structure remains a central topic of QCD study, including measurement of the proton radius (PRad), nucleon form factors, and 3D imaging of the nucleon. High precision measurement of electron scattering also contributes to the test of the Standard Model, which is the goal of the completed Qweak, PREX-II/CREX and the future MOLLER and SoLID PVDIS experiments. UVA researchers are also involved in building the next generation nuclear physics facility in the United States, the Electron Ion Collider (EIC), highlighted as Recommendation 3 in the LRP. The ongoing program as well as planning for the EIC require a substantial effort in QCD theory and computing. Furthermore, the LRP discusses the increasing tension between the precision measurement of the muon g-factor and its theoretical prediction (the g-2 experiment), tensions in the unitarity test of the Cabibbo-Kobayashi-Maskawa matrix, which are investigated in the Nab and pNab experiments with neutrons, and in PIONEER with pions, and the completion of Hadronic Parity Violation studies with npdgamma and nHe3. To read the full text of the LRP, please see https://nuclearsciencefuture.org/

A new program on spin-polarized fusion (SPF) was showcased in the LRP Sidebar 11.5. After a decade of research funded by UVA's research initiative and three-cavalier funds, SPF received its first federal funding from DOE’s FES office, coincidentally, also on October 4^th. For more information, see https://science.osti.gov/fes.

Last but not least, Recommendation 1 affirms that the LRP “must draw on the talents of all in the nation”. This entails, specifically, raising the compensation of graduate students accounting for the cost of living, and lowering barriers to allow for opportunities in STEM for all, while ensuring that resources to guarantee a safe and respectful environment for everyone are made available.

Prof. Arnold studies the theory of the strong, weak, and electromagnetic interactions at extremely high, relativistic temperatures, such as in the very early Universe (less than a millionth of a second after the Big Bang) or in relativistic collisions in heavy ion accelerators. Topics he has studied include investigating why there is significantly more matter than anti-matter in the Universe and understanding the properties of quark-gluon plasmas. The theoretical methods used for these very high energy problems (as much as a quadrillion degrees Kelvin) can also be applied to certain ... More>

Professor Baeßler does research in fundamental symmetries, that is, precision tests of the Standard Model of Elementary Particles. His main activities are devoted to physics with cold neutrons at the SNS in Oak Ridge/Tennessee. He conducts experiments that study neutron beta decay (Nab and pNab). In addition, he is testing gravity with cold and ultracold neutrons at the ILL in Grenoble/France (GRANIT), and he is determining the magnetic moment of the muon (g-2) at Fermilab and ... More>

Professor Cates conducts research in three diverse areas spanning atomic, nuclear, and medical physics. Unifying these activities is the use of optical pumping and spin exchange, techniques that make it possible to polarize the spins of electrons, atoms and nuclei using light sources such as lasers. Critical to such research is the study of spin interactions during atomic collisions, spin-relaxation at surfaces, and numerous aspects of laser physics. More>

Professor Keller conducts research in spin physics at the intersection of high-energy, nuclear, and condensed matter physics, with interests in hadron spin structure, physics beyond the standard model, spin-sensitive phenomena, and mapping the inner structure of composite spin systems. This research involves the study of quark and gluon dynamics as well as the study of spin degrees of freedom to probe polarized observables. This research could also be ... More>

Professor Liuti´s research involves theoretical studies of the quark and gluon internal dynamics of the proton. The fundamental interactions of quarks and gluons are governed by the beautifully concise Lagrangian of quantum chromodynamics (QCD), however, to be able to understand the mechanisms generating the proton mass, spin and mechanical properties in terms of quarks and gluons is one of the biggest challenges in physics today. Professor Liuti's work has been focused on understanding how the nucleon gets its spin from its fundamental ... More>

In the so called confinement region quarks interact strongly to form protons and neutrons. Understanding the structure of the nucleon in the confinement region in terms of Quantum Chromo Dynamics (QCD), the fundamental theory governing the strong interaction between quarks, presents a great challenge to physicists. Professor Liyanage´s research is focused on understanding the neutron structure. He is the principal spokesperson of a recently completed Jefferson Lab experiment, E01-012, that performed a precision measurement of the neutron spin structure in the nucleon resonance ... More>

Quantum Chromo-Dynamics (QCD) provides an excellent description of subnuclear phenomena at high energies. However, at lower energies observables cannot be calculated exactly from QCD; one has to resort to models or parametrizations which are consistent with the basic symmetries of QCD. Near-threshold electromagnetic production of pions from nucleons are ideal processes in which to test these theoretical approaches. We are engaged in measuring these processes at the Jefferson Laboratory (JLab) and at the new High Intensity Gamma Source (HIGS) located at the Duke Free Electron Laser ... More>

Professor Paschke’s research activity focuses on precision measurements of parity-violation in electron scattering at Jefferson Lab, in Newport News Virginia. These measurements have proven to be a useful tool for the study of the building blocks of the atomic nucleus and for testing the completeness of the Standard Model of electroweak interactions. A recently completed series of experiments address a range of topics, including strange quarks in nuclei, nuclear structure in a ²⁰⁸Pb nucleus, and the electroweak coupling of the nucleons. Prof. Paschke is also actively ... More>

Professor Počanić is studying basic symmetries and conservation laws manifest at low and intermediate energies, with the aim of obtaining new stringent constraints on the dynamics of the two fundamental short-range interactions: the electroweak and the strong. This work requires precise measurements of the elementary decay and scattering processes typically involving the simplest particles in nature: mesons, leptons, and nucleons. More>

My research in theoretical particle physics is based on string theory, and I am especially interested in the connections between gauge and string theories. More>

Professor Zheng conducts research at the Thomas Jefferson National Accelerator Facility (JLab). Her research interest includes study of the nucleon structure, especially the spin structure of the neutron using the polarized 3He target. The nucleon structure is determined by how quarks and gluons interact with each other, thus such information could reveal some fundamental properties of the strong interaction and QCD. Another major aspect of Prof. Zheng's research is parity violation (PV) in electron deep inelastic scattering (DIS). By measuring the PVDIS asymmetry off a hydrogen and a ... More>