UNC-CH Physics and Astronomy Colloquium

Akaa Daniel Ayangeakaa, United States Naval Academy

“Shape coexistence and triaxiality in atomic nuclei”

The study of shapes and shape-related phenomena in atomic nuclei have been major themes of research in nuclear physics for more than half a century. In this talk, I will present results of measurements aimed at studying shape coexistence, a rare phenomenon where states located at similar excitation energies, but associated with different intrinsic deformations, coexist and interact. The talk will focus primarily on the electromagnetic properties of low-lying states in 72,76Ge investigated via multi-step Coulomb excitation. The experiments exploit state-of-the-art instruments: the advanced gamma-ray tracking array, GRETINA, and the charged-particle detector, CHICO2. The influence of the axial asymmetry parameter on the shape of these nuclei will be highlighted and the observations confronted with results of calculations within contemporary nuclear models. In addition, new experimental evidence characterizing the precise nature of triaxial deformation in 76Ge will be presented, in connection with the determination of nuclear decay matrix elements involved in neutrinoless double-beta decay (0). The themes and techniques presented in this talk will be an important component of the scientific program at FRIB, the Facility for Rare Isotope Beams that will start operations within the next 1 – 2 years.

Please note the room change.