This award will support a cooperative research project in medium energy physics between Professor Robert P. Redwine of the Massachusetts Institute of Technology and Professor Osamu Hashimoto of the Institute for Nuclear Study, University of Tokyo. The scientists will cooperate in investigating the interactions of pions with nuclei in the energy range around and above the delta resonance. This project is based on a great amount of work that has been carried out in the past 15 years on interactions in the delta resonance region, especially at LAMPF in Los Alamos. This experimental and theoretical work has increased considerably the understanding of the interaction mechanism itself and specific nuclear structure issues as well. As expected, many aspects of the pion-nucleus interaction in this region are dominated by the formation of the delta resonance in the nucleus. This has proved to be both an advantage and a disadvantage. As the delta does appear to be so dominant, use of this dominance in descriptions of the interaction have been reasonably successful. On the other hand, this dominance can mask other interesting physics issues. In this project, the investigators will involve scientists from several other leading U.S. and Japanese research institutions who have been conducting experiments of this type. In particular, scientists from the Brookhaven National Laboratory and the Japanese Laboratory for High Energy Physics (KEK) will be involved. With the commissioning of new spectrometers at the KEK laboratory in Japan, studies with higher energy pions will enter a new phase and U.S. scientists will have the opportunity to play an important role in this opening field.
