Simultaneous γ-ray and electron spectroscopy of 182,184,186 Hg isotopes Stryjczyk, Marek García Ramos, José Enrique IDS Collaboration We would like to thank Tibor Kibédi for fruitful discussions regarding internal conversion coefficients. We acknowledge the support of the ISOLDE Collaboration and technical teams. This project has received funding from the European Union's Horizon 2020 research and innovation programme Grant Agreements No. 654002 (ENSAR2), 665779, and 771036 (CoG MAIDEN). T.R.R. acknowledges the computing resources and assistance provided by GSI-Darmstadt and CCC-UAM. This work has been funded by FWO-Vlaanderen (Belgium), by GOA/2015/010 (BOF KU Leuven), by the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12), by the Slovak Research and Development Agency (Contract No. APVV-18-0268), by the Slovak Grant Agency VEGA (Contract No. 1/0651/21), by Spanish Grants No. FPA2015-64969-P, FPA2015-65035-P, FPA2017-87568-P, FPA2017-83946-C2-1-P, RTI2018-098868-B-I00, PPID2019-104002GB-C21, PID2019-104390GB-I00, PID2019-104714GB-C21, and PID2019-104002GB-C21 funded by MCIN/AEI/10.13039/50110001103 and “ERDF A way of making Europe” and by European Regional Development Fund, ref. no. SOMM17/6105/UGR, by Science and Technology Facilities Council (STFC) of the UK Grant No. ST/R004056/1, ST/P005314/1, ST/P003885/1, ST/V001035/1, ST/P004598/1, and ST/V001027/1, by the Bundesministerium für Bildung und Forschung under contract no. 05P21PKCI1, by the Institute of Atomic Physics project CERN-RO/ISOLDE, by the Polish Ministry of Education and Science under Contract No. 2021/WK/07 and by the Academy of Finland (Finland) Grant No. 307685. Background: The mercury isotopes around N=104 are a well-known example of nuclei exhibiting shape coexistence. Mixing of configurations can be studied by measuring the monopole strength ρ2(E0), however, currently the experimental information is scarce and lacks precision, especially for the Iπ→Iπ (I≠0) transitions. Purpose: The goals of this study were to increase the precision of the known branching ratios and internal conversion coefficients, to increase the amount of available information regarding excited states in Hg182,184,186, and to interpret the results in the framework of shape coexistence using different models. Method: The low-energy structures in Hg182,184,186 were populated in the β decay of Tl182,184,186, produced at ISOLDE, CERN and purified by laser ionization and mass separation. The γ-ray and internal conversion electron events were detected by five germanium clover detectors and a segmented silicon detector, respectively, and correlated in time to build decay schemes. Results: In total, 193, 178, and 156 transitions, including 144, 140, and 108 observed for the first time in a β-decay experiment, were assigned to Hg182,184,186, respectively. Internal conversion coefficients were determined for 23 transitions, out of which 12 had an E0 component. Extracted branching ratios allowed the sign of the interference term in Hg182 as well as ρ2(E0;02+→01+) and B(E2;02+→21+) in Hg184 to be determined. By means of electron-electron coincidences, the 03+ state was identified in Hg184. The experimental results were qualitatively reproduced by five theoretical approaches, the interacting boson model with configuration mixing with two different parametrizations, the general Bohr Hamiltonian, the beyond mean-field model, and the symmetry-conserving configuration-mixing model. However, a quantitative description is lacking. Conclusions: The presence of shape coexistence in neutron-deficient mercury isotopes was confirmed and evidence for the phenomenon existing at higher energies was found. The new experimental results provide important spectroscopic input for future Coulomb excitation studies. 2023-09-13T08:11:39Z 2023-09-13T08:11:39Z 2023-07-06 journal article M. Stryjczyk et al. Simultaneous γ-ray and electron spectroscopy of 182,184,186 Hg isotopes. Physical Review C 108, 014308. [DOI: 10.1103/PhysRevC.108.014308] https://hdl.handle.net/10481/84382 10.1103/PhysRevC.108.014308 eng info:eu-repo/grantAgreement/EC/H2020/654002 info:eu-repo/grantAgreement/EC/H2020/665779 info:eu-repo/grantAgreement/EC/H2020/771036 http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional American Physical Society