Direct Reactions with Exotic Beams (DREB2016)

Normal and intruder configurations in the island of inversion

14 Jul 2016, 11:00

15m

Scotiabank Theatre (St. Mary's University)

Contributed Oral/Poster Shell evolution through direct reactions - Spectroscopy of nuclear levels and nuclear shapes through direct reactions

Speaker

Dr Kathrin Wimmer (The University of Tokyo)

Description

In the island of inversion a coexistence of low-lying states with different shapes results from the relatively small energy gap between normal, spherical $sd$ configurations and deformed intruder $fp$ configurations arising from excitations beyond the $N=20$ shell gap. The ground states of these shape coexisting configurations have been identified in ${}^{30,32}$Mg, however, band-like structures built on top are yet to be identified. Additionally from the excitation energy of negative parity states, resulting from the coupling of $sd$ with $fp$ neutrons, the size of the shell gap can be determined. In-beam gamma-ray spectroscopy of ${}^{30,32}$Mg and surrounding nuclei has been performed in knockout reactions at the NSCL using the GRETINA gamma spectrometer coupled to the S800 spectrograph. Using different reaction channels, normal or intruder configurations can be populated selectively. We will present new results on the structure of ${}^{30,32}$Mg and discuss the transition into the island of inversion.