Strongly coupled enhanced-deformation band in Pr131

An enhanced-deformation (ED) rotational band with unusual characteristics has been discovered in the odd-Z nucleus Pr131. The dynamical moment of inertia J(2)=(50–60)ħ2 MeV-1 and the extracted quadrupole moment Q0 = 5.5 ± 0.8 eb (β2=0.32±0.05) are comparable with other ED bands (sometimes called ‘‘superdeformed’’) in the mass A∼130 region. The two signature partners of the ED band are connected by dipole transitions which can be followed down to a K=9/2 bandhead. The nature of this band differs from all other ED bands in the A∼130 region since the i13/2 intruder neutron orbital is unoccupied.