https://doi.org/10.1140/epja/s10050-020-00206-9
Regular Article - Theoretical Physics
High-spin doublet band structures in odd–odd 
Tl isotopes
1
Department of Physics, SP College Srinagar, Srinagar, Jammu and Kashmir, 190 001, India
2
Department of Physics, University of Kashmir, Srinagar, 190 006, India
3
Cluster University Srinagar, Goji Bagh, Srinagar, Jammu and Kashmir, 190 008, India
4
Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai, 400 005, India
5
Department of Physics, Islamic University of Science and Technology, Awantipora, Jammu and Kashmir, 192 122, India
* e-mail: sheikhahmad.phy@gmail.com
Received:
4
May
2020
Accepted:
23
July
2020
Published online:
3
August
2020
The basis space in the triaxial projected shell model (TPSM) approach is generalized for odd–odd nuclei to include two-neutron and two-proton configurations on the basic one-neutron coupled to one-proton quasiparticle state. The generalization allows to investigate odd–odd nuclei beyond the band crossing region and as a first application of this development, high-spin band structures recently observed in odd–odd Tl isotopes are investigated. In some of these isotopes, the doublet band structures observed after the band crossing have been conjuctured to arise from the spontaneous breaking of the chiral symmetry. The driving configuration of the chiral symmetry in these odd–odd isotopes is one-proton and three-neutrons rather than the basic one-proton and one-neutron as already observed in many other nuclei. It is demonstrated using the TPSM approach that energy differences of the doublet bands in 
Tl and 
Tl are, indeed, small. However, the differences in the calculated transition probabilities are somewhat larger than what is expected in the chiral symmetry limit. Experimental data on the transition probabilities is needed to shed light on the chiral nature of the doublet bands.
© Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature, 2020
