Signature inversion in the pi h(9/2)circle times vi(13/2) oblate band of (TI)-T-190

High-spin states in Tl-190 have been studied experimentally using the Gd-160(Cl-35, 5n) fusion-evaporation reaction at beam energies of 167-175 MeV. A rotational band built on the pih(9/2)circle timesnui(13/2) configuration with oblate deformation has been established. Spin values have been firmly assigned to the pih(9/2)circle timesnui(13/2) oblate band by combining the present in-beam experimental results with the complementary alpha-gamma correlation measurements of Bi-194 alpha decay. With the configuration and spin-parity assignments, the low-spin signature inversion has been revealed for the pirh(9/2)circle timesnui(13/2) oblate band. It is the first experimental observation of low-spin signature inversion for a band associated with the oblate pih(9/2)circle timesnui(13/2) configuration. The low-spin signature inversion could be interpreted in the framework of the quasiparticles plus rotor model including a J dependent proton-neutron residual interaction.