High spin states in ${}^{127,129,131}\mathrm{La}$ have been investigated using the ${}^{100}\mathrm{Mo}{(}^{32}\mathrm{S},p4n),\hspace{0.5em}E=160\mathrm{}\hspace{0.5em}\mathrm{MeV},$ ${}^{100}\mathrm{Mo}{(}^{34}\mathrm{S},p4n),\hspace{0.5em}E=155\mathrm{}\hspace{0.5em}\mathrm{MeV},$ and ${}^{100}\mathrm{Mo}{(}^{36}\mathrm{S},p4n),\hspace{0.5em}E=160\mathrm{}\hspace{0.5em}\mathrm{MeV}$ reactions, respectively. γ rays were detected using the EUROBALL IV ${(}^{127,131}\mathrm{La})$ and EUROGAM II ${(}^{129}\mathrm{La})$ arrays. The results have enabled the negative parity yrast band, built on the $\pi h_{11/2}$ orbital at low spin, and the lowest lying $(\pi ,\alpha )=(+,\pm \frac{1}{2})$ bands to be extended to higher spins. The positive parity, $\alpha =-\frac{1}{2},$ bands in ${}^{127,129}\mathrm{La}$ and the positive parity, $\alpha =\frac{1}{2},$ band in ${}^{127}\mathrm{La}$ can be interpreted, with the aid of cranked Nilsson-Strutinsky calculations, as examples of smoothly terminating bands in valence space based on both signatures of the $\pi \left[{(g}_{7/2}{d}_{5/2}{)}^5{(h}_{11/2}{)}^2\right]\otimes \nu \left[{(g}_{7/2}{d}_{5/2}{)}^x{(h}_{11/2}{)}^6{(d}_{3/2}{s}_{1/2}{)}^2\right]$ configuration, where $x=12,14\mathrm{}$ for ${}^{127,129}\mathrm{La},$ respectively. The favored $\alpha =-\frac{1}{2}$ bands of these configurations are predicted to terminate at ${\frac{95}{2}}^{+}$ and ${\frac{83}{2}}^{+},$ respectively, and experimentally the bands are observed to within two transitions of these terminating states. The data for the positive parity, $\alpha =\frac{1}{2},$ band in ${}^{129}\mathrm{La}$ do not allow any firm conclusions to be made regarding the high spin structure of this band. The positive parity bands in ${}^{131}\mathrm{La}$ have a different structure at high spin compared with the lighter nuclei. In this case the bands may be interpreted in terms of a $\pi \left[{(g}_{7/2}{d}_{5/2}{)}^5{(h}_{11/2}{)}^2\right]\otimes \nu \left[{(g}_{7/2}{d}_{5/2}{)}^{12}{(h}_{11/2}{)}^8{(d}_{3/2}{s}_{1/2}{)}^4\right]$ configuration relative to a ${}^{100}\mathrm{Sn}$ core.

• Received 14 April 2000

DOI:https://doi.org/10.1103/PhysRevC.62.034315