Shape coexistence in the neutron-deficient $^{188}$Hg investigated via lifetime measurements

Siciliano, M, Zanon, I, Goasduff, A, John, PR, Rodríguez, TR, Péru, S, Deloncle, I, Libert, J, Zielińska, M, Ashad, D
et al (show 34 more authors) (2020) Shape coexistence in the neutron-deficient $^{188}$Hg investigated via lifetime measurements. Phys. Rev. C, 102. 014318 - ?.

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Shape coexistence in the $Z \approx 82$ region has been established in mercury, lead and polonium isotopes. Even-even mercury isotopes with $100 \leq N \leq 106$ present multiple fingerprints of this phenomenon, which seems to be no longer present for $N \geq 110$. According to a number of theoretical calculations, shape coexistence is predicted in the $^{188}$Hg isotope. The $^{188}$Hg nucleus was populated using two different fusion-evaporation reactions with two targets, $^{158}$Gd and $^{160}$Gd, and a beam of $^{34}$S, provided by the Tandem-ALPI accelerators complex at the Laboratori Nazionali di Legnaro. The channels of interest were selected using the information from the Neutron Wall array, while the $\gamma$ rays were detected using the GALILEO $\gamma$-ray array. The lifetimes of the excited states were determined using the Recoil Distance Doppler-Shift method, employing the dedicated GALILEO plunger device. Using the two-bands mixing and rotational models, the deformation of the pure configurations was obtained from the experimental results. The extracted transition strengths were compared with those calculated with the state-of-the-art symmetry-conserving configuration-mixing (SCCM) and five-dimentional collective Hamiltonian (5DCH) approaches in order to shed light on the nature of the observed structures in the $^{188}$Hg nucleus. An oblate, a normal- and a super-deformed prolate bands were predicted and their underlying shell structure was also discussed.

Item Type: Article
Additional Information: v1: 13 pages, 10 figures, comparison between IBM-CM and SCCM calculations; v2: 16 pages, 13 figures, discussion on the mixing amplitudes from the experimental B(E2) values, comparison between SCCM and 5DCH calculations
Uncontrolled Keywords: nucl-ex, nucl-ex, nucl-th
Depositing User: Symplectic Admin
Date Deposited: 02 Mar 2020 15:11
Last Modified: 09 Jan 2021 02:23
DOI: 10.1103/PhysRevC.102.014318
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