Electromagnetic Transition Rates in ²⁸Mg

Neutron rich Mg isotopes far from stability belong to the island of inversion, a region where the single particle energy state description of the shell model breaks down and the predicted configuration of the nuclear states becomes inverted. Nuclei in this region also exhibit collective behaviour in which multiple particle interactions play a significant role in nuclear wavefunctions and transitions. This can be observed through electromagnetic transition strength measurements.

Using TIGRESS in conjunction with the TIGRESS Integrated Plunger for charged particle transitions at TRIUMF, Canada's particle accelerator centre, an experiment was performed to measure the lifetime of the first excited state in ²⁸Mg. This experiment used both the Doppler Shift Attenuation Method and the Recoil Distance Method, which exploit the Doppler shift of gamma rays emitted in flight in order to be sensitive to lifetimes of both short- and long-lived excited states in the nucleus. The current state of data analysis and the impacts on nuclear physics will be discussed.