Single-particle and collective motions from nuclear many-body correlation (PCM2025)

Towards the shell structure at Island of Stability - Investigation of heavy-ion fusion reactions in near symmetric systems

5 Mar 2025, 15:10

1m

Main Lecture Hall (University of Aizu)

Poster session

Speaker

Jiatai Li (Center for Nuclear Study, University of Tokyo)

Description

Search for the Island of Stability (IoS) has been one of the most attractive problems in modern nuclear physics. IoS is predicted to exist in the neutron-rich vicinity near Z = 114, N = 184, the Super Heavy Element (SHE) within are anticipated to have a lifetime longer than a year while the lifetime of SHE synthesized in the lab are on the order of ms. The huge enhancement in the stability is expected to be triggered by the increasing shell stabilization. However, the existence of IoS is predicted based on the shell model of nuclei lighter than lead, therefore energies of single-particle levels require further confirmation when extrapolating to the SH region.

Heavy-ion fusion reaction is a promising approach to reach IoS, and it is also powerful in exploring the nuclear structure, in particular for highly excited states. Due to the neutron-rich nature of IoS, stable beam-target combinations can not be used, neutron-rich RI beams need to be applied instead. Similar to what had been done so far, Ca beam and actinide target seems to be a reasonable choice, while the beam intensity of neutron-rich Ca beam is currently too low at any facilities around the world. An alternative is to use double magic ${}^{132}$Sn, which is located at the fission peak of ${}^{238}$U. However, with the reduced mass asymmetry of the entrance channel, the formation probability of the compound nucleus will be hindered significantly. Therefore, pioneering studies of fusion reactions in near symmetric systems are needed.

A fusion reaction using ${}^{136}$Xe beam to bombard a natural zinc target has been performed at HIMAC. The fusion-evaporation cross section was extracted based on the $\alpha$ decay spectroscopy of the evaporation residues. In this presentation, details of the experimental setup and the data analysis will be given.