Low-spin states of ${}^{157}\mathrm{Dy}$ have been studied using the JUROGAM II array, following the ${}^{155}\mathrm{Gd}$ ($\alpha$, 2n) reaction at a beam energy of 25 MeV. The level scheme of ${}^{157}\mathrm{Dy}$ has been expanded with four new bands. Rotational structures built on the $\left[523\right]5/2^{-}$ and $\left[402\right]3/2^{+}$ neutron orbitals constitute new additions to the level scheme as do many of the inter- and intraband transitions. This manuscript also reports the observation of cross ${\mathrm{I}}^{+}\to {\left(\mathrm{I}–1\right)}^{-}$ and ${\mathrm{I}}^{-}\to {\left(\mathrm{I}–1\right)}^{+}$ E1 dipole transitions interlinking structures built on the $\left[523\right]5/2^{-}$ (band 5) and $\left[402\right]3/2^{+}$ (band 7) neutron orbitals. These interlacing band structures are interpreted as the bands of parity doublets with simplex quantum number $s=–i$ related to possible octupole correlations.

• Received 19 April 2019
• Revised 10 May 2019

DOI:https://doi.org/10.1103/PhysRevC.100.034322