Speaker
Description
The evolution of shell structure in unstable nuclei is a hot topic in modern nuclear physics. In neutron-rich nuclei, inversions in ordering of single-particle orbitals have been observed, which can lead to the disappearance of conventional magic numbers. Among the N=7 isotones, the relative ordering of the neutron s- and p-orbitals in $^{10}$Li has been the subject of long-standing debate. While theoretical calculations consistently predict an inversion of s- and p-orbitals in the ground-state of $^{10}$Li, experimental results remain inconclusive.
Given that the ground state of $^{11}$Be is known to have a dominant s-wave component (∼80%) with a d-wave admixture (∼20%). As a result, the single-proton transfer reaction $^{11}$Be(d,$^{3}$He)$^{10}$Li preferentially populates s-wave resonances in $^{10}$Li. By precisely measuring the resonance energy of this state, we aim to clarify whether an inversion between the s and p orbitals occurs in $^{10}$Li. As part of the AT-TPC campaign, the experiment was performed in 2025 at the EN course of the Research Center for Nuclear Physics (RCNP), Osaka University. A primary ¹⁸O beam was used to produce the secondary beam ¹¹Be with the energy around 26.5 MeV/u. The ATTPC is filled with C$_3$D$_8$(~460 torr). The scattered light particles (H, He) were detected within the AT-TPC, while the heavy ions (Li, Be) were measured by the telescope located at the downstream of the AT-TPC.
This talk will present preliminary results from the inelastic scattering $^{11}$Be(d,d’)$^{11}$Be, as well as the excitation energy spectrum of $^{10}$Li populated via the $^{11}$Be(d,$^{3}$He) reaction.