Collective and single-particle states at high excitation energy

Abstract

Damping of high-lying single-particle states was investigated by the study of decay by proton emission from high-lying states in Nb-91, populated by the Zr-90(alpha, t) reaction at E-alpha = 180 MeV. In addition to decay to the ground state of Zr-90, semi-direct decay was observed to the low-lying (2(+)/5(-) and 3(-)) phonon states, confirming the conclusion from other experiments that phonon states play an important role in the damping process of the single-particle states. Furthermore, the population and decay of isobaric analogue states of Zr-91, which are located at an excitation energy of about 10 - 12 MeV in Nb-91, has been studied in the same reaction