New insights in the first backbending region of heavy Dy isotopes

The Li-7-induced incomplete fusion reaction Gd-158/160(Li-7,p(d,t)xn) (beam energy 56 MeV) has been used to investigate in detail the first backbendin g region of the heavy stable Dy nuclei Dy-160/162. In Dy-162, the measured low interaction strength between the ground band and the Stockholm band of \V-gs\ approximate to 17 keV confirms the predicted existence of a node in the interaction strength for nuclei with neutron number between N = 96 and N = 98, which has not been accessed earlier. The crossing frequency between the ground band and the Stockholm band in (DY)-D-162 was measured to be (h ) over bar w(c) approximate to 320 keV, which is about 40 keV higher than t he expected value of (h) over bar w(c) approximate to 280 keV known from ot her nuclei in this mass region. In Dy-160, an yrare band could be establish ed for the first time in a nucleus with a very large interaction strength. From fits to level energies as well as hom branching ratios, an interaction strength of \V-gs\ approximate to 220 keV was extracted.