Speaker
Description
The evolution of shell structure in neutron-rich nuclei remains a central topic in nuclear physics, particularly the disappearance of traditional magic numbers and the persistence or emergence of sub-shell closures far from stability. In this presentation, we report recent progress on direct-reaction studies of light exotic nuclei ${}^{16}$C and ${}^{12}$Be using ATTPC and solenoidal spectrometers, with emphasis on the N = 8 and Z = 6 shell structures.
First, we present the result of probing ${}^{16}$C with inelastic reactions using Active Target Time Projection Chamber coupled to solenoidal magnetic field. The inelastic-scattering results indicate that the third $2^+$ state is dominated by proton excitation, giving evidence for the persistence of the Z = 6 proton sub-shell closure in neutron-rich carbon isotopes. Second, we discuss ${}^{12}$Be's result from ${}^{12}$Be(p,d)${}^{11}$Be using similar experimental setup, where the measured single-particle strength provides direct evidence for the breakdown of the traditional N = 8 shell closure in the beryllium isotopic chain.
Finally, we report the current progress of the ${}^{12}$Be(d,p)${}^{13}$Be experiment performed at RCNP using the AT-TPC with downstream charged-particle identification (silicon+GAGG). Together, these studies demonstrate the power of active-target to probe shell evolution in weakly bound nuclei.
To address these questions, we carried out the ${}^{12}{\rm Be}(d,p){}^{13}{\rm Be}$ experiment at RCNP using the AT-TPC together with downstream zero-degree silicon for charged particle detection. The measurement has been completed, and we have proceeded to the data reconstruction and analysis stage. But the analysis project is still in an early phase without drawing final conclusion yet. In this meeting, we will report the present status of the experiment and share our early-stage data analysis and reveal key features of the dataset.