HIGH-SPIN STATES IN TA-175 - AN ACUTE EXAMPLE OF DELAYED CROSSING FREQUENCY

High spin states in Ta-175 are populated by the Gd-160 (F-19,4n) Ta-17 5 reaction. This experiment, carried out at the HI-13 tandem accelerat or at the China Institute of Atomic Energy which measured the gamma-ga mma coincidences, gives rise to a new level scheme. Two important new features are embedded in this scheme. First, the seven decay sequences built on 1/2 [541], 7/2 [404], 5/2 [402], and 9/2 [514] proton Nilsso n configurations are significantly extended to higher spins. For examp le, for the 1/2 [541] band, the levels have extended from 22-/2 to 61- /2 and, for [404] band, from 21-/2 to 41-/2. Second, compared to the n eighboring even-even nuclides, the neutron AB crossing frequency built on the h9/2 proton Nilsson state 1/2 [541] is significantly larger, w hich according the conventional cranking shell model (CSM) is an anoma ly. In this paper, this large crossing frequency is also discussed wit hin the framework of the projected shell model. It is shown that this anomaly found in CSM can be satisfactorily explained, thus suggesting an alternative understanding.