Low-spin signature inversion in the πh_9/2⊗νi_13/2 oblate band of ¹⁹⁰Tl

High-spin states in ¹⁹⁰Tl have been studied experimentally by using the ¹⁶⁰Gd(³⁵Cl,5n) fusion-evaporation reaction at beam energies of 167 and 175 MeV. A rotational band built on the πh_9/2⊗νi_13/2 configuration with oblate deformation has been established for ¹⁹⁰Tl. Spin values are assigned by adopting the results from α-γ decay work for ¹⁹⁴Bi found in the literature. With the configuration and spin-parity assignments, the low-spin signature inversion has been revealed for the πh_9/2⊗νi_13/2 oblate band in ¹⁹⁰Tl. It is the first experimental observation of low-spin signature inversion for a band associated with the oblate πh_9/2⊗νi_13/2 configuration. The low-spin signature inversion for the oblate πh_9/2⊗νi_13/2 band can be interpreted by the two-quasiparticle-plus-rotor model including a J-dependent p-n residual interaction.