Systematic study of spin assignments and signature inversion of π<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="italic">h</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>⊗ν<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="italic">h</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>bands in doubly odd nuclei around<i>A</i>∼130

According to the argument of excitation energy systematics, new spin values are assigned to the lowest observed states of the \ensuremath{\pi}${\mathit{h}}_{11/2}$\ensuremath{\bigotimes}\ensuremath{\nu}${\mathit{h}}_{11/2}$ bands for doubly odd nuclei $^{124,126,130,132,134}\mathrm{La}$, $^{130--134}\mathrm{Pr}$, $^{136,138}\mathrm{Pm}$, and $^{138}\mathrm{Eu}$, and possible new spin values are discussed for doubly odd nuclei $^{120--130}\mathrm{Cs}$. Based on these new spin assignments, two systematic features of the \ensuremath{\pi}${\mathit{h}}_{11/2}$\ensuremath{\bigotimes}\ensuremath{\nu}${\mathit{h}}_{11/2}$ bands are revealed. First, the low spin signature of the \ensuremath{\pi}${\mathit{h}}_{11/2}$\ensuremath{\bigotimes}\ensuremath{\nu}${\mathit{h}}_{11/2}$ band is inverted for all doubly odd nuclei discussed in the present work. Second, the observed inversion spin increases with increasing neutron number for Cs and La isotopes. These features are in agreement with the recent systematic calculations based on the particle-triaxial-rotor model, with the inclusion of zero-range residual interaction between unpaired proton and neutron of Semmes and Ragnarsson, performed by Tajima. \textcopyright{} 1996 The American Physical Society.