Cover Story (Issue3, 2024) | First measurement of the ground-state mass of²²Al helpsto evaluate theab-initiotheory

Author: Prof. BaohuaSun (Beihang University)

How the strong interaction binds the ingredients (proton and neutron) of atomic nuclei, is the central quest of nuclear physics. Nuclear physicists have been addressing this question with different experimental techniques and theoretical approaches. Among them, themass or binding energy of a nucleus, reflecting the interplay of all forces atwork within the nucleus, has played a key role in the journey of understanding the nucleus and testing the theories.

In a recent study [1] published by thegroup in Lanzhou, the ground-state mass of²²Al, the known lightest bound Al isotope, has been measured for the first time with a precision of 10keV. Such high precision was achieved by using the newly developed Bρ-defined IMS technique at CSRe. With the new mass, they determined the mirror energy differences (MEDs) of the 1^1,2states in²²Al and²²F,the so-called mirror partners, with the uncertainty of about 50 keV. This precise value allows a crucial test of the state-of-the-artab-initiocalculations in an odd-odd mirror pair. They concluded that the substantial occupation of s_1/2orbit is vital in understanding the significant isospin symmetry breaking, and supports the suggested halo structure in the 1⁺₁state of²²Al.

References

[1]M.Z. Sun et al., Chinese Physics C 48 034002(2024)