Speaker
Description
Over the past several years, extensive studies have been devoted to the structure of neutron-rich tin isotopes, which possess a closed proton shell, with ¹³²Sn being a doubly magic nucleus. For this reason, these nuclei play a particularly important role in testing the validity of the nuclear shell model and serve as a benchmark for theoretical predictions. Information obtained in this region of the nuclear chart is essential for developing reliable extrapolations toward even more neutron-rich isotopes.
In the experiments studied, the tin nuclei are produced by the $\beta^{-}$ decay of indium isotopes and via the emission of $\beta^{-}$ delayed neutrons or, in some cases, two $\beta^{-}$ delayed neutrons ~\cite{MA1,MA2}. Data from this mass region are also highly relevant from an astrophysical perspective, as they contribute to a better understanding of the r-process nucleosynthesis responsible for the formation of heavy elements in the universe.
In the present study, we focus on the excited states in $^{124}$Sn populated in the $\beta^{-}$ decay of $^{124}$In investigated in an experiment performed at the ISOLDE Decay Station (IDS). In addition to the aforementioned motivations, an additional driving factor for studying the structure of this nucleus is the possible occurrence of the rare two-neutrino double beta decay (2$\beta^{-}$) in $^{124}$Sn. Although $^{124}$Sn is a stable nucleus and the single $\beta^{-}$ decay is energetically forbidden, the 2$\beta^{-}$ decay is allowed and has been the subject of several investigations ~\cite{BB1, BB2, BB3}. A better understanding of the nuclear structure of $^{124}$Sn will improve the reliability of theoretical predictions for this process and may help identify excited states that are more likely to be involved in the transition.
The current analysis of the $\beta^{-}$ decay of the two isomeric states of $^{124}$In includes $\beta$–$\gamma$, $\beta$–$\gamma$–$\gamma$, and $\gamma$–$\gamma$ coincidence spectra. A detailed comparison of the previously established decay scheme with the new experimental data led to the reassignment of six $\gamma$ transitions to different positions in the level scheme. These changes were reinforced by finding new gammas that fit the changed scheme very well. To sum up the preliminary analysis, 21 new transitions were identified and included in the scheme, and 17 new excited levels were obtained.
\begin{thebibliography}{9}
\bibitem{MA1}
M. ~Piersa, A. ~Korgul \textit{et al.}, Phys. Rev. C 99, 024304 (2019).
\bibitem{MA2}
M. ~Piersa-Siłkowska, A. ~Korgul \textit{et al.}, Phys. Rev. C 104, 044328 (2021).
\bibitem{BB1}
A. S. ~Barabash, Ph. ~Hubert \textit{et al.}, Nucl. Phys. A 807, 269281 (2008)
\bibitem{BB2}
M. ~Horoi, A. ~Neacsu, Phys. Rev. C 93, 024308 (2016)
\bibitem{BB3}
D. ~Patel, P. C. ~Strivastava \textit{et al.}, Nucl. Phys. A 1042, 122808 (2024)
\end{thebibliography}
