Zr同位素及同核异能态结构的投影壳模型研究 刘艳鑫 中科院近代物理研究所/湖州师范学院 指导教师：孙扬教授 周小红研究员 2012年4月12-16日第十四届全国核结构会议 湖州

I . Introduction II. Theoretical model III. Results and discussions IV. Summary

Quadrupole deformation of the nuclear ground states I. Introduction Shapes of nuclei Prolate Oblate Quadrupole deformation of the nuclear ground states M. Girod, CEA Bruyères-le-Châtel Few nuclei have oblate ground states (~86% are prolate in their ground state) Phys Rev C64 (2001) 037301

What’s the nature of the new isomer? A new isomer with a half-life of 620 ±150 ns has been identified in 108Zr. What’s the nature of the new isomer? A tetrahedral shape isomer?

The parity of the tetrahedral shape isomer is negative. Ex>1MeV, J≥4 The parity of the tetrahedral shape isomer is negative. N. Schunck et al., Phys. Rev. C 69, 061305(R) (2004).

II. Theoretical model Projected shell model (PSM) 1. Multi-quasiparticle configuration 2. Angular momentum projection operator 3. Hamiltonian K. Hara, Y. Sun, Int. J. Mod. Phys. E 4 (1995) 637

Triaxial projected shell model (TPSM) 1. Triaxial Nilsson Hamiltonian 2. Three-dimensional angular momentum projection 1). J. A. Sheikh and K. Hara, Phys.Rev.Lett. 82, 3968 (1999). 2). Y. Sun et al., Phys. Rev. C 61, 064323 (2000).

III. Results and discussions The study of 102-106Zr by the projected shell model (PSM) 1. Moment of inertia Y. X. Liu, Y. Sun, X. H. Zhou et al. Nucl. Phys. A, 2011, 858: 11-31

2. Signature splitting in 1-qp bands

Nature of the isomer in very neutron-rich 108Zr 1. Calculated potential-energy surfaces for 108Zr and 110Zr P. Möller et al., Atom. Data Nucl. Data Tables, 2012, 98: 149-300

2. Oblate shape results

2. Oblate shape with triaxiality

IV. Summary ♦ 1. The variation of moments of inertia in even–even nuclei has been described as crossings of 2-qp bands with the ground band. ♦ 2. By discussing the signature splitting, we have concluded that the nuclei studied in this paper could be regarded as axially symmetric systems. ♦ 3. To confirm whether this isomer has the tetrahedral shape or not, the determination of the decay scheme including spins and parities, and the measurement of the band structure above the isomer, are required from future measurements.

Thanks