Band Structures of the Nucleus ¹²⁹Cs

High-spin states in ¹²⁹Cs are populated via the ¹²²Sn (¹¹B, 4n) reaction at beam energies of 55 and 60MeV. Two additional bands are placed in the level scheme and the previously known bands are extended to higher spins. The results are compared to the cranked shell model calculations and to the systematics of the adjacent Cs isotpoes. One of the new bands is interpreted as the γ-vibrational band built on the π h_11/2 orbital. The possible configuration for another new band is discussed. Upbend caused by (ν h_11/2)² alignment is observed both in the favored and unfavored sequences of the π h_11/2 configuration. The band based on the π g_7/2 configuration at low pins forks around spin 17/2, and the two different S-bands are attributed to (ν h_11/2)² and (π h_11/2)² rotational alignments, respectively.