Nuclear Physics

Welcome to the home of the UConn Nuclear Physics Group!

The goal of our experimental and theoretical efforts is to advance the quantitative understanding of the rich variety of strong interaction phenomena in terms of quantum chromodynamics (QCD).

Our interests range from low-energy experiments with rare ions at Argonne National Lab, over medium-energy scattering of electrons and photons off protons and nuclei at Jefferson National Lab (JLab) to theoretical studies of the quark-gluon plasma probed in high energy reactions at Brookhaven National Lab (BNL) and Large Hadron Collider (LHC) . Our group is involved in preparatory studies of the future Electron-Ion Collider.

Our activities offer graduate and undergraduate students a vibrant and inclusive environment to engage in cutting edge research. We are committed to promoting an inclusive community in nuclear physics, and broadening the participation in nuclear physics among members of traditionally underrepresented groups.

Nuclear Experiment

  • Exotic Mesons.  The stable bound states in QCD consist of three quarks (baryons), three antiquarks (antibaryons), or quark-antiquark pairs (mesons) bound by a strongly interacting gluon field. Somewhat higher in mass, a new class of unstable “exotic” mesons is expected to exist, in which the gluonic field is excited above its ground state configuration. The GluEX experiment (Fig. 1) at Jefferson Lab uses a 9 GeV polarized photon beam to search for these exotic mesons, and map their spectrum. The group of Prof. Richard Jones is active in the production and analysis of data from this experiment.
  • Spin Structure of the Nucleon. Imaging of quarks inside nucleons is in the focus of the CLAS experiment, Fig. 2. The extensive research program of Prof. Kyungseon Joo's group spans from studies ofgeneralized and transverse momentum dependent distribution functions, over hadron formation, to the nucleon resonance N physics. The group leads the design and construction of major detector components.
  • 3D Imaging of the Nucleon.  The not yet well-explored 3D structure is also in the focus of Prof. Andrew Puckett’s group involved in experiments in JLab’s Halls A (Fig. 3) and B that will address orbital angular motion of quarks, and the spatial distribution of charge at small distance scales. The group plays a lead role in the development of Cherenkov counters for efficient identification of charged particles, and data analysis.
  • Nuclear structure beyond the valley of stability.  The group of Prof. Alan Wuosmaa probes the structure of neutron-rich nuclei far beyond the valley of stability through rare-isotope beam experiments at the Argonne National Laboratory, Fig. 4. Research in the group includes also studies of clustering phenomena in light nuclei, investigations of astrophysical nucleosynthesis through the interactions of exotic nuclear species, and development of advanced instrumentation for nuclear physics.

Nuclear Theory

  • Lattice QCD studies.  The quark-gluon structure of hadrons is described in terms of parton distribution functions, which roughly speaking tell us the probability to find a given type of parton (quark or antiquark of flavor u, d, s, ... or a gluon) carrying a certain fraction of the nucleon momentum. The theoretical description of such functions requires to solve QCD in the strong coupling regime which is only possible using nonperturbative methods. The group of Prof. Luchang Jin uses the rigorous first-principle approach based on  lattice QCD Monte Carlo simulations to compute parton distribution functions and explore the internal structure of the nucleon.
  • Theory of Hadron Interactions at High Energies.   In the collisions of hadrons in high-energy experiments at BNL and LHC extremely high densities of partons are created. One main research area in the group of Prof. Alex Kovner is the study of the hadronic interactions in the high-energy regime with particular focus on the derivation of the QCD evolution equations at high partonic density and study its consequences for inclusive as well as exclusive observables. Other research activities include the finite temperature deconfining phase transition and studies of structure of vacuum in confining gauge theories using variational methods and ideas based on spontaneous breaking of magnetic symmetry.
  • Hadron Structure and Chiral Symmetry Breaking.  The symmetry of the QCD Lagrangian of the light quarks is are not reflected in the hadronic spectrum, but spontaneously broken which is accompanied by the emergence of Goldstone bosons identified with the lighest hadrons, pions, kaons and η-mesons. The group of Prof. Peter Schweitzer employs effective chiral theories described in terms of quark, antiquark and Goldstone boson degrees of freedom to predict hadronic properties such as the distribution of internal pressure forces inside the nucleon.