Theoretical Nuclear & Particle Physics

A fundamental goal in modern theoretical nuclear physics is to incorporate present knowledge about the interaction between elementary particles into the understanding of the most basic building block of stable matter - the atomic nucleus. This need to understand the nucleus is apparent in many areas of physics, ranging from speculative questions about the nature of neutron stars and the supernovae that produce them, to fundamental questions about orgin and character of the nuclear force, to very practical issues like the interaction of nuclei and nuclear radiation with matter.

Neutrons and protons are viewed as the traditional constituents of nuclei. The strong force between these two can be explained as an interaction via the exchange of heavy bosons. This picture is very successful in explaining a variety of nuclear properties. However, particle theory views quarks and gluons as the ultimate constituents of the strong interaction, modeling existing particles as multi-quark and gluon systems. These pictures are complementary, but up to now, neither of them fully describes the nucleus in the detail and precision demanded by modern experiments.

The research activities linked to the Institute of Nuclear and Particle Physics at Ohio University cover a wide range of topics. We are interested in a description of the nuclear force in terms of effective hadronic field theories. Up to now this understanding of the nuclear force has been the most successful way to describe few-nucleon systems and meson production in two-nucleon collisions at intermediate energies. Despite the successes, there are still fundamental questions to be answered about effective coupling constants, the nature of form factors, and the range of validity of this particular description of the nuclear force.

In a complementary approach to the understanding of nuclei, we concentrate on electromagnetic probes of the nucleus, i.e., electrons, positrons, muons, and photons, which interact primarily via the electromagnetic force with particles whose charges and magnetic moments are well known. The advantage of electromagnetic probes is that the interaction is well understood theoretically.

Currently we are working on pion and kaon production in nucleons and nuclei where the incoming energy is deposited by a photon or by a scattering electron (virtual photon production). We are also working on improved relativistic wave functions for finite nuclei and their implications for electromagnetic probes, as in quasielastic scattering of electrons or production of antiprotons in a nucleus.

A vast amount of the information we possess about nuclei is provided by experiments in which protons or neutrons are scattered from composite nuclei. Because of the complicated nature of the strong interaction, a theoretical description of these reactions has to rely on a detailed multiple scattering theory. We are interested in the development and numerical implementation of techniques in a multiple scattering approach. This should allow us to describe the scattering of protons and neutrons from nuclei in a microscopic and 'ab initio' fashion with a realistic two-nucleon force and ground state wave function of the nucleus as input.

Associated Faculty: Elster, Phillips, Prakash

Emeritus Faculty: Onley, Wright