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rotation and alignment of high-j orbitls in transfermium nuclei

rotation and alignment of high-j orbitls in transfermium nuclei. Dr. Xiao-tao He College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics Chifeng • China ， 2010,07,25-31. Motivation.

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rotation and alignment of high-j orbitls in transfermium nuclei

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  1. rotation and alignment of high-j orbitls in transfermium nuclei Dr. Xiao-tao He College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics Chifeng • China，2010,07,25-31

  2. Motivation Exploration of the island of stability with highmass and charge, i.e. the regionof superheavyelements (SHE) has been one of the fundamental questions innature science！ • How to get structure information about superheavy elements (SHE) ?

  3. Motivation • αdecays • spins and parities: Spectroscopy of collective rotation Difficulty: The extremely low production cross-sections. It can rarely reveal the detailed spectroscopic information of SHE in the experiments. • Tansfermium nuclei (Z = 102,N = 152) are the heaviest system accessible in present in-beam experiment

  4. Motivation 102 100 the study of these deformed transfermium nuclei may provide an indirect way to access the single particle states of the next closed spherical shells. ε2=0.25

  5. Rotational Band Some experimental results Even-even nuclei: 254No β2=0.27±2 P. Reiter, et al., PRL82 (1999) 509.

  6. Rotational Band Even-even nuclei: 252No β2=0.28±2 R.-D. Herzberg, et al., PRC, 65 (2001) 014303

  7. Rotational Band Even-even nuclei: 250Fm β2=0.28±2 J. E. Bastin, et al., PRC 73 (2006) 024308.

  8. Rotational Band Odd-neutron nuclei: 253No P. Reiter, et al., PRL 95, 032501 (2005). R.-D. Herzberg,et al., Eur. Phys. J. A (2009)

  9. Rotational Band Odd-proton nuclei: 251Md This band: 1/2[521] Ground state band: 7/2[514] A. Chatillon, et al., PRL 98, 132503 (2007).

  10. Rotational Band Odd-proton nuclei: 255Lr The structures are tentatively assigned to be based on the 1/2[521] and 7/2[514] Nilsson states, respectively. S. Ketelhut,et al., PRL 102, 212501 (2007).

  11. High-K structure R.D. Herzberg et al., Nature 442 (2006) 896

  12. High-K structure 250Fm B. Sulignano,et al., EPJA 33 (2007) 327.

  13. High-K structure 250Fm P. T. Greenlees,et al., PRC 78 (2008) 021303

  14. A. P. Robinson,et al., PRC 78 (2008) 034308

  15. High-K structure H. B. Jeppesen,et al., PRC 79, 031303(R) (2009).

  16. High-K structure 257Rf 11/2−[725] the ground-state configuration in 257Rf is 1/2+[620]. J. Qian, et.al., PRC 79, 064319 (2009).

  17. High-K structure Odd-proton nuclei: 255Lr Assuming the quadrupole deformation of the band to be β2 = 0.3 (typical for nuclei in this region). the lowest observed sequence is built upon the [624]9/2+ Nilsson state. H. B. Jeppesen, et al., PRC 80, 034324 (2009).

  18. Theoretical study Cranked Shell Model with Particle number conserving method treatment for the pairing correlation: Hp single particle part : H0

  19. Theoretical study In rotating frame： HCSM is diagonalized in the Cranked Many-Particle Configuration (CMPC) space, we get the solution of CSM Hamiltonian： Di：Real

  20. Theoretical study The angular momentum alignment in ： Kinematic MoI： Dynamic MoI：

  21. Theoretical study Parameters • The Nilsson parameters (κ,μ) are taken from: S.G. Nilsson, et al., Nucl. Phys. A131 (1969) 1. * The deformation parameters ε2 =0.29 , ε4=0.02 for 252,253,254No and 250Fm, ε2 =0.30 , ε4=0.02 for 251Md. * The effective pairing interaction strengths ( G0 for monopole pairing and G2 for quadrupole pairing ) in unite of MeV are given as follow, G0p=0.45, G0n=0.35, G2p=0.02, G2n=0.02 * Proton: Ecut : 0.60 ω0CMCP space ~ 1000 Neutron: Ecut : 0.50 ω0CMCP space ~ 1000

  22. Theoretical results Even-even nuclei: Experimental and theoretical J(1) of the bands in 250Fm, 252No and 254No.

  23. Theoretical results Odd-neutron nuclei: Experimental and theoretical J(1) of the band in 253No.

  24. Theoretical results Odd-proton nuclei: Experimental and theoretical J(1) of the band in 251Md.

  25. Theoretical results The cranked Nilsson orbitals near the Fermi surface in 251Md

  26. Theoretical results Occupation probabilities of each cranked orbital near the Fermi surface (include both α=±1/2) in 251Md.

  27. Theoretical results The total angular momentum alignment <Jx>, and the separate contributions to <Jx> from neutron and proton in 251Md.

  28. Theoretical results The contribution to <Jx> from each neutron (N=5,6,7) and proton (N=4,5,6,7) major shells for the 1/2−[521] band in 251Md.

  29. Theoretical results The contributions to <Jx> from the particle in each proton cranked orbitalμ, jx(μ) and the interference term jx(μν) between cranked orbitals μ and ν for the 1/2−[521] band in 251Md, which are simply denoted by μ and μν, respectively.

  30. Theoretical results The contributions to <Jx> from the particle in each proton cranked orbitalμ, jx(μ) and the interference term jx(μν) between cranked orbitals μ and ν for the 7/2+[624] band in 253No, which are simply denoted by μ and μν, respectively.

  31. Summary * The observed bands are reproduced very well by the theoretical results. * Exploration of behaviors of these bands at high spin shows that there is backbending taking place at hω ≈ 0.275 MeV in bands of 252,253,254No. *α = −1/2 band in 251Md is predicted. It is very encouraged to find that there is a backbending occurring at very low frequency, hω ≈ 0.15 MeV,which might be during the possible observed frequency. * The neutron 2h11/2 (1/2[761]) and proton 1j15/2 (1/2[770]) orbitals play a very important role in the rotational properties of transfermium nuclei.

  32. Thank you !

  33. Thank you !

  34. Welcome to Nanjing !

  35. Theoretical results Nilsson S G et al., NPA, 131 (1969) 1.

  36. Theoretical results Nilsson S G et al., NPA, 131 (1969) 1.

  37. Theoretical results Nilsson S G et al., NPA, 131 (1969) 1.

  38. Theoretical results Nilsson S G et al., NPA, 131 (1969) 1.

  39. Theoretical results Nilsson S G et al., NPA, 131 (1969) 1.

  40. Theoretical results Nilsson S G et al., NPA, 131 (1969) 1.

  41. Theoretical results

  42. Theoretical results T. Bengtsson, I. Ragnarsson, NPA436 (1985) 14-82

  43. Theoretical results T. Bengtsson, I. Ragnarsson, NPA436 (1985) 14-82

  44. rotation and alignment of high-j orbitls in transfermium nuclei Dr. Xiao-tao He College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics Prof. Zhong-zhou Ren Department of Physics, Nanjing University Prof. En-guang Zhao Institute of Theoretical Physics, Chinese of Academy of Sciences. Prof. Shu-xin Liu & Jin-yan Zeng School of Physics, Peking University Chifeng • China，2010,07,25-31

  45. Theoretical study Odd-mass transfermium nuclei are seldom studied; Cranked shell model are seldom used. We used the cranked shell model to calculate the collective rotation of SHE. Collective rotational bands provide important testing ground to check the extrapolations of current models to SHE region!

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