Excitation of Nuclei by Antiproton Annihilation at Rest

Research leading to the detailed characterization of antiproton annihilation in nuclei has resulted in three publications during the past year. We have reported on neutron yields and angular distributions from annihilation in uranium. This work is important to our SHIVA Star subcritical microfission measurements currently in progress at the Phillips Laboratory, Kirtland AFB. Proton spectra indicate the presence of multinucleon annihilation in carbon and uranium targets. This is important in determining the premission yield of nucleons in annihilation on uranium. The existence of rare hypernuclei formed in antiproton annihilation on uranium and bismuth has been observed. These states live a fraction of a nanosecond, and are of considerable interest to theorists trying to understand the binding of particles in heavy nuclei.