Trends in the energy staggering of the pih(11)/(2)nui(13/2) and pih(11)/(2)
nuh(11/2) bands in the mass 160 and 130 regions, respectively, have been in
vestigated in order to better understand the origin of signature inversion.
While the A approximate to 160 nuclei behave in a consistent manner, a mor
e complicated scenario is observed in the mass 130 region. As a result of o
ur experiments on the lightest Pr nuclei, the systematics of these Z = 59 n
uclei have been extended, which aids in the understanding of the latter reg
ion. Triaxial deformation, a pn interaction, and quadrupole pairing are con
sidered as possible contributors to this effect. As all the chiral-twin ban
ds that are known have signature inversion in the favored band, a possible
link between the two phenomena should be considered.