Ponente
Descripción
The ground-state shape change as a function of the number of protons or neutrons is a typical Quantum Phase Transition (QPT) phenomenon. In the southwest of $^{208}$Pb, a shape transition from prolate to oblate, with a critical point around N=116, is proposed to occur as the neutron number increases (D. Cline, Annu. Rev. Nucl. Part. Sci. 36, 683 (1986)). To date, such evolution has been experimentally established in Pt and Os isotopic chains by gamma spectroscopy, while IBM calculations suggest that the transition occurs more rapidly as one moves from Z = 76 (Os) toward Z = 70 (Yb) (K. Nomura, et al., Phys. Rev. C 84, 054316 (2011)). Additionally, many K-isomers were identified in this region despite the proximity to the critical point N=116 (G. D. Dracoulis, et al., Rep. Prog. Phys. 79, 076301 (2016)), which provides a good opportunity to explore the level scheme below the isomer. With recent upgrades in beam intensities at RIKEN and the high efficiency of the upcoming advanced gamma detector array, more exotic nuclei are now within reach for detailed investigation. Here, we propose to search for K-isomers in the Z=70-74, N~116 region, aiming to provide deeper insights into the shape transition in this area.
