Speaker
Description
In this gamma spectroscopy analysis, we aim to measure the spectroscopic quadrupole moments of excited states and electromagnetic transition rates in neutron-deficient 140Sm. The experimental data was collected during a Coulomb excitation experiment at ISOLDE in 2017, utilizing a 140Sm beam on a 208Pb target and the Miniball HPGe array alongside a CD particle detector.
The chain of samarium isotopes exhibits a diverse range of nuclear shapes, from spherical at the N=82 shell closure to well-deformed for both the neutron-rich isotopes beyond A=154 and the very neutron-deficient ones below A=134. The nucleus 152Sm is a well-known example for so-called X(5) symmetry at the transition from spherical vibrational to deformed rotational behavior. The case of 140Sm, on the other hand, is a candidate for a nucleus with E(5) symmetry, corresponding to the triple point in the phase diagram for shape phase transitions between spherical, oblate, and prolate shapes. This makes electromagnetic matrix elements in 140Sm sensitive benchmarks for theoretical nuclear structure models. We will present preliminary results from our analysis during the workshop.