The strong interaction sector of the Standard Model of particle physics, described by the theory of quarks and gluons, QCD, presents a rich variety of phenomena, asymptotic freedom, confinement, and dynamical chiral symmetry breaking among the most fundamental ones, which determine the structure and dynamics of hadrons and nuclei. The understanding of those phenomena drives significant contemporary experimental and theoretical research efforts, where a variety of observables and processes are studied in order to shed light onto the complex landscape of strongly interacting matter. Through the application of theoretical approaches known as effective theories, this project aims at studying baryons, their static as well as dynamic properties which are relevant to the mentioned phenomena and to the present experimental efforts at several laboratories. Baryons are subatomic particles, such as nucleons or hyperons. A key objective of the project is to develop the effective theory tools that will permit a more accurate description of baryons at low and intermediate energies. The project is also invested in the research participation of graduate and undergraduate students, and it has the potential to enhance diversity in theoretical nuclear physics through its location at Hampton University.
The goals of the project concentrate on the study of the physics of hadrons at low and intermediate energies, domains where the non-perturbative nature of the strong interactions is most prominent. The understanding of many of the hadron observables, such as form factors, electromagnetic polarizabilities, low energy hadron-hadron scattering, nuclear forces, etc, remains a work in progress where there is broad theoretical, experimental and lattice QCD activity. Through the use of the methods of effective theories, which are rigorously anchored in the strictures of QCD, a description of hadronic physics in those domains is possible, and with it an understanding of interrelations between different observables becomes possible. The program will concentrate on the study of baryons, namely protons, neutrons and their cousins the strange baryons, as well as their low lying excited states. It will entail the further development of effective theory tools, in this case chiral effective theory and the 1/Nc expansion, and their applications to baryon observables, in particular those not well understood, such as low energy (virtual) Compton scattering and corresponding polarizabilities, single-spin asymmetries in electron-nucleon scattering, low energy pion-nucleon scattering, and applications to results being obtained in lattice QCD calculations on baryon structure and the dependencies on quark masses.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
