Seminarium Fizyki Jądra Atomowego
sala 1.01, ul. Pasteura 5
2019-11-14 (10:15) 
mgr Marek Stryjczyk (doktorant na Uniwersytecie Katolickim w Leuven, Belgia)
Shape coexistence in atomic nuclei studied through β decay at ISOLDE, CERN
Shape coexistence is a phenomenon known for more than 50 years. Initially, it was considered a rarity, which occurs throughout the nuclear chart only in a few selected isotopes. However, this belief has evolved towards the conviction that shape coexistence occurs in almost all nuclei [1]. Thanks to developments in radioactive ion beam production and in experimental techniques, it became possible to study exotic nuclei with an extreme proton-to-neutron ratio. During this seminar, I will discuss the occurrence of shape coexistence in two regions: around the light, neutron-rich nickel-66 and around the heavy, neutron-deficient mercury-182, studied in both cases through β decay.In the first part of the seminar, the recently published results of a 66Co β decay study to 66Ni will be discussed [2]. Nickel-66 has been proposed to exhibit triple shape-coexistence, with low-lying spherical, oblate and prolate 0+ states [3]. The decay pattern and the selective β-feeding of the 0+ and 2+ states strongly supports this interpretation [2]. The details of the analysis, including the application of Bayesian methods in the analysis of nuclear-physics data, will be presented, and the experimental results will be compared with state-of-the-art Monte Carlo shell model calculations.In the second part of the seminar, neutron-deficient mercury-182 will be discussed. This isotope lies in one of the regions where shape coexistence is most prominent [1,4,5]. In particular, the presence of E0 components in the Iπ→Iπ (I≠0) transitions is interpreted as a mixing between states with a different [1]. In order to measure these components, during the experiment, performed at the ISOLDE Decay Station in autumn 2018, a dedicated conversion-electron detector was used [6]. The preliminary results will be discussed and compared with theoretical models as well as with other experimental studies [7].
References:
[1] K. Heyde, J.L. Wood, Rev. Mod. Phys 83, 1467 (2011)
[2] M. Stryjczyk et al., Phys. Rev. C 98, 064326 (2018)
[3] S. Leoni et al., Phys. Rev. Lett 118, 162502 (2017)
[4] B.A. Marsh et al., Nature Physics 14, 1163 (2018)
[5] S. Sels et al., Phys. Rev. C 99, 044306 (2019)
[6] P. Papadakis et al., Eur. Phys. J. A 54, 42 (2018)
[7] K. Wrzosek-Lipska et al., Eur. Phys. J. A 55, 130 (2019)
References:
[1] K. Heyde, J.L. Wood, Rev. Mod. Phys 83, 1467 (2011)
[2] M. Stryjczyk et al., Phys. Rev. C 98, 064326 (2018)
[3] S. Leoni et al., Phys. Rev. Lett 118, 162502 (2017)
[4] B.A. Marsh et al., Nature Physics 14, 1163 (2018)
[5] S. Sels et al., Phys. Rev. C 99, 044306 (2019)
[6] P. Papadakis et al., Eur. Phys. J. A 54, 42 (2018)
[7] K. Wrzosek-Lipska et al., Eur. Phys. J. A 55, 130 (2019)