New Levels of $^{157}$Pm

Gamma rays in coincidence with isotopically-identified fission fragments using VAMOS++ and EXOGAM, produced using $^{238}$U on a $^{9}$Be target, at an energy around the Coulomb barrier have been reported. In the present work, we have combined data from the in-beam mass- and Z-gated spectra with the $\gamma$-$\gamma$-$\gamma$-$\gamma$ data from $^{252}$Cf (SF) to assign transitions and levels in $^{157}$Pm. In contrast to Hwang, 2009, the transitions previously assigned to $^{156}$Pm are all seen in the M-Z gated spectra of $^{157}$Pm and are not seen in the M-Z gated spectra of $^{156}$Pm. The new expanded levels of $^{157}$Pm are remarkably similar to those of the levels in $^{155}$Pm, which have been assigned as a rotational band built on $\pi$ 5/2 [532].