Speaker
Description
Neutron-rich nuclei near doubly-magic 132Sn offer a valuable testing ground for exploring both nuclear structure and the astrophysical r-process. Investigation of neutron-branching ratios in this region offers benchmark testing of theoretical descriptions of neutron-rich nuclei, and the N = 82 shell closure provides an isotonic chain of waiting-point nuclei critical to r-process trajectories and the final pattern of elemental abundances [1-2]. Thanks to the advanced radioactive beam production and high-purity mass separation at CERN [3-4], the opportunity to study nuclei in this region with minimal contamination is possible. This presentation will focus on a recent beta-decay spectroscopy measurement performed at the ISOLDE Decay Station, where the decay of 134In was measured to further test the statistical model description of spherical delayed neutron emitters with low, nuclear-level densities [5]. For the first time, energy correlations in two-neutron emission were measured using the Neutron dEtector with multi-neutron (Xn) Tracking (NEXT) array for an r-process nucleus. This capability made it possible to identify two-neutron-emitting states in the 134Sn daughter and, subsequently, the long-sought i13/2 neutron single-particle state in 133Sn [6-9]. Both the experimental results and comparison with theoretical models will be presented, which provides crucial information towards nuclear structure in the 132Sn region.
References:
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[2] M. R. Mumpower et al.; Progress in Particle and Nuclear Physics, 86 86-126 (2016)
[3] R. Catherall, W. Andreazza, M. Breitenfeldt, A. Dorsival et al.; J. Phys. G 44, 094002 (2017)
[4] V. Fedosseev, K. Chrysalidis, T. Day Goodacre, B. Marsh et al.; J. Phys. G 44, 084006 (2017)
[5] J. Heideman et al.; Phys. Rev. C 108, 024311 (2023)
[6] P. Hoff, P. Baumann, A. Huck; Hyperfine Interactions 129, 141 (2000)
[7] A. Korgul et al.; EPJ A 7, 167 (2000)
[8] K. Jones et al.; Nature 465, 454 (2010)
[9] J. Allmond et al.; Phys. Rev. Lett. 112, 172701 (2014)