Existence of an Exotic Torus Configuration in High-Spin Excited States of 40Ca

We investigate the possibility of the existence of the exotic torus configuration in the high-spin excited states of Ca-40. We here consider the spin alignments about the symmetry axis. To this end, we use a three-dimensional cranked Skyrme Hartree-Fock method and search for stable single-particle configurations. We find one stable state with the torus configuration at the total angular momentum J = 60 h and an excitation energy of about 170 MeV in all calculations using various Skyrme interactions. The total angular momentum J = 60 h consists of aligned 12 nucleons with the orbital angular momenta Lambda = +4, +5, and +6 for spin-up or -down neutrons and protons. The obtained results strongly suggest that a macroscopic amount of circulating current breaking the time-reversal symmetry emerges in the high-spin excited state of Ca-40.