Nuclear Physics

Experimental Faculty: Haeberli, Knutson, Quin
Theoretical Faculty: Balantekin, Friedman

Groups at Wisconsin conduct experiments in both low and intermediate energy nuclear physics. The emphasis is on properties of the strong interactions in nuclei and on fundamental questions in physics. The theoretical research covers a wide range of phenomena.

Experimental Nuclear Physics

For many years, Wisconsin has been a leader in nuclear physics research. Three professors (Barschall, Haeberli and Herb) have received the Bonner Prize, the highest award in experimental nuclear physics. Wisconsin physicists developed the first practical pressure-insulated electrostatic accelerator (in the 1930’s), and developed one of the first intense sources of negative ions. This led to the installation (in 1959) of the first tandem accelerator in the United States. The first source of negative polarized ions for a tandem accelerator was developed at Wisconsin in 1966. More recently, work on the development of polarized gas targets has led to installation of UW-designed polarized internal targets at the HERA electron storage ring in Germany and the proton Cooler Storage Ring at IUCF. The current research program is broadly based. Experiments in low energy nuclear physics are carried out at the local tandem accelerator laboratory, located in Sterling Hall. The group also has an active research program at the IUCF storage ring and is involved in research projects at several laboratories in Europe. The research is focussed in the areas of symmetry tests, properties of few-nucleon systems and instrumentation development. Most of the experimental activities involve the study of spin physics.

Experimental facilities available at the local laboratory include a model EN tandem accelerator which is equipped with an intense source of polarized negative hydrogen and deuterium ions, along with more conventional ion sources. Auxiliary equipment includes a large, high-efficiency NaI gamma-ray spectrometer, a laser-pumped polarized ³He target, a tritium gas target for production of polarized secondary neutron beams, and a large number of other specialized systems.

The off-campus work is carried out mainly at IUCF, at PSI in Switzerland, and at the HERA ring in Germany. At HERA the group participates in the HERMES experiment which is studying the spin structure of the proton and the neutron.

Theoretical Nuclear Physics

The theoretical nuclear group maintains close contacts with other institutions in this country (e.g. Michigan State, National Institute for Nuclear Theory (Seattle), Argonne National Laboratory and Lawrence Berkeley Laboratory) as well as in Australia, Japan, Europe and Latin America, which result in collaboration and frequent visitors from those institutions. Research is currently being pursued here on compound and pre-equilibrium effects and statistical fluctuations in nuclear reactions, high energy heavy-ion reactions with projectile fragmentation, nuclear multi fragmentation, deeply inelastic heavy-ion collision, phase transitions in nuclear and hadronic systems, nuclear structure and symmetry principles, supersymmetry in many-body systems, neutrino physics and astrophysics, the solar neutrino problem, dark matter detection, neutrino effects in type-II supernovae (see entry under Theoretical Neutrino Astrophysics), semi-classical techniques applied to heavy ion reactions, and collective effects in nuclear reactions and models.