Search

High-spin states in neutron-rich indium isotope 116In have been observed for the first time by using incomplete fusion of 7Li on a 116Cd target at a beam energy of 42 MeV. A negative-parity band with πg9/2−1⊗νh11/2 configuration and a pair of positive-parity doublet bands with πg9/2−1⊗ν(g7/2/d5/2)h11/22 configurations have been identified. The positive-parity doublet bands are tentatively interpreted as chiral doublet bands, which is supported by the adiabatic and configuration-fixed constrained triaxial relativistic-mean-field and multiparticle plus rotor model calculations. This observation reports a possible new region of chirality in neutron-rich A≈ 120 mass region.

Nearly degenerate positive-parity doublet bands and several E1 transitions between positive- and negative-parity bands have been identified in 76Br. These experimental observations are interpreted as the coexistence of chirality and octupole correlations, based on the analysis of detailed γ-ray spectroscopy with the precise lifetime measurements and theoretical calculations, and play a key role to explore the simultaneous breaking of chiral and reflection symmetry and their interplay. The present work provides the first test for chirality in the A≈80 mass region by lifetime measurements, and firstly elucidates the formation of chiral geometry in the presence of the octupole correlations in Br isotopes, leading to the conclusion that the reflection symmetry breaking catalyzes rather than destroys chiral symmetry breaking in nuclear systems.

Two nearly degenerate positive-parity bands with the πg9/22⊗νg9/2−1 configuration and three nearly degenerate negative-parity bands with the πg9/2(p3/2,f5/2)⊗νg9/2−1 configuration have been identified in 81Kr. They are interpreted as chiral doublet bands and pseudospin-chiral triplet bands, which is supported by the constrained covariant density functional theory and the multiparticle plus rotor model calculations. The present work reports two new chiral configurations πg9/22⊗νg9/2−1 and πg9/2(p3/2,f5/2)⊗νg9/2−1, and the first example of pseudospin-chiral triplet bands involving the π(p3/2,f5/2) pseudospin doublet.