Rotational alignments in $^{235}$Np

The $j_{15/2}$ neutron-orbital alignment has been studied by exploring $\gamma$- ray transitions of yrast states in $^{235}$Np, populated utilizing the nucleon-transfer reaction $^{237}$Np($^{116}$Sn,$^{118}$Sn). The experiment was carried out at Argonne National Laboratory using the {\small GAMMASPHERE/CHICO} setup. The ground-state band for this nucleus has been delineated to high spin for the first time, with the $\alpha = +1/2$ and $\alpha = -1/2$ signature partners reaching spin- state population levels of $49/2^{+}$~$\hbar$ and $47/2^{+}$~$\hbar$, respectively. Definite assignments for these intraband transitions were established through $\gamma$-ray cross correlations between $^{235}$Np and $^{118}$Sn and events where at least three $\gamma$ rays corresponding to Np-like particles were detected. These transitions reveal clear upbends in the aligned-angular momentum and kinematic moment of inertia plots; this observation is indicative of a strong interaction between an aligned $s$-band and the $g$-band in $^{235}$Np. The role of the $\nu j_{15/2}$, $\pi h_{9/2}$, and $\pi i_{13/2}$ alignment mechanisms in the deformed U$-$Pu region will be discussed in light of the current spectroscopic data and in the framework of the CSM.