Investigation Of The High Spin Rotational Bands In ^{165,167,169,171}Tm Using A Particle Number Conserving Method

Since the 1950s,the rotational properties of deformed nuclei have been one of the important research fields of nuclear physics.With the construction of heavy ion accelerator and the progress of detection technology,it is possible to produce nuclear high-spin states.In the process of the high-speed rotation of the nucleus,a variety of new physical phenomena appear which can help people to understand the nuclear structure more deeply.In 1971,the discovery of the backbending phenomenon breaks the traditional understanding of the nuclear high-spin states.It is a milestone in the development of high-spin physics to realize the influence of rotation frequency on the single-particle motion.The pairing correlations are very important for nuclear rotational properties.Particle number conserving method was proposed by Prof.Jin-Yan Zeng et al.,which is used to treat the pairing correlations in the nuclei.In contrary to the conventional Bardeen-Cooper-Schrieffer or Hartree-Fock-Bogolyubov approaches,in the particle number conserving method,the Hamiltonian is solved directly in the truncated Fock space.So the particle number is conserved from beginning to the end and the blocking effects are treated exactly.In this work,the cranked shell model with pairing correlations treated by a particle number conserving method is used to investigate,the high spin rotational bands in 165,167,169,171Tm.The experimental moments of inertia and alignments with the rotational frequency,and bandhead energy i.e.,of the 1-quasiparticle and 3-quasiparticle in Tm isotope are reproduced very well by the calculation.The calculated results reproduce the strength of the backbending of the ground state band ?1/2+[411]in 165,167,169Tm with the increase of neutron number.It is proved that there is a sharp backbending in 165Tm,a smooth upbending in 167Tm and a relatively sharp backbending in 169Tm,and it is predicted that the upbending in 171Tm will be very slow.By analyzing the change of the occupation probability of energy levels near the Fermi surface with rotational frequency and the contribution of each orbit to the alignment,the backbendings are understood clearly.In addition,by investigating the effect of the size of the neutron N=98,102 subshell on the moment of inertia,it is found that the backbending(upbending)depends not only on the shell structure,but also on the specific high j orbit near the Fermi surface.