Document Type : Original Article

Authors

Department of Physics, Payame Noor University, PO BOX 19395-3697 Tehran, Iran

Abstract

Back-bending phenomenon which occurs at high spin states of some heavy mass nuclei has been studied, for the first time, by using the ratio of electromagnetic reduced transition probabilities B(M1) / B(E2) within the Projected Shell Model (PSM). In this model, all angular momenta are projected on the symmetry axis of the deformed nucleus, which makes shell model calculations much easier. The electric quadrupole transition probability  B(E2) and the magnetic dipole transition probability B(M1) are sensitive to the nuclear shape deformation and nuclear charge distribution, respectively. As a result, any change in the nuclear rotation speed can change the transition probability ratios at high spins. Our ratio findings at high state spins in even - even 152-164Dy isotopes confirm the previous back-bendings seen in these isotopes, in good agreement wth the experimental data. Increasing spectroscopic quadrupole moments with spin is another high spin phenomenon in heavy mass nuclei studied in this paper. While intrinsic quadrupole moments are constant for each Dy isotope, this study shows that spectroscopic (observed) quadrupole moments are increasing with spin.

Keywords

Main Subjects

  1. A Bohr and B Mottelson,Nuclear structure“ World Scinetific (1998).
  2. S G Nilsson, Phys. Medd. 29 (1955) 16.
  3. K Hara and Y Sun, J. Mod. Physics E 4, 4 (1995) 637.
  4. Y Sun and K Hara, Phys. Commun 104 (1997) 245.
  5. J Bardeen, L N Cooper, and J R Schrieffer Rev. 108 (1957) 1175.
  6. B Slathia, R Devi, and S K Khosa, Phys A 943 (2015) 39.
  7. T Shizuma, et al., Rev. C 69 (2004) 024305.
  8. P Verma, et al., Nucl. Phys. A 918 (2013) 1
  9. G Krishan, et al., Pram. J. of Phys. 83 (2014) 341.
  10. B Slathia, R Devi, and S K Khosa, Indi. J. phys. 90 (2016) 1165.
  11. V Velaquez, et al., Phys. A 653 (1999) 355.
  12. Z Wen Hua and G Jian Zhong, Phys. Lett. 27, 1 (2010) 012101.
  13. Y Sun and J L Egido, Nuc Phys. A 580 (1994) 1.
  14. A N Behkami and M N Nasrabadi, Commun. Theor. Phys. 37, 4 (2002)
  15. M Shahriarie, S Mohammadi, and Z Firouzi, Korean Phys. Soc. 76 (2020) 8.
  16. P Möller, et al., Data Nucl. Data Tables 109 (2016) 1.
  17. J A Sheikh, Y Sun, and P M Walker, Phys. Rev. C 57 (1998) R26.
  18. J Suhonen,”Electromagnetic Multipole Moments and Transitions” Springer, Berlin, Heidelberg (2007).
  19. D Ram, R Devi, and S Khosa, Pramana J. Phys. 80 (2013) 953.
  20. B Castel and I S Towner, “Modern theories of nuclear moments”, Clarendon Press (1990).
  21. B A Brown, “Lecture notes in nuclear structure physics, National Super Conducting Cyclotron Laboratory” Michigan State University (2005).
  22. R F Casten, “Nuclear Structure from a Simple Perspective Oxford University Press (2000).
  23. K S K Krane, “Introductory Nuclear Physics”, John Wiley and Sons (1987).
  24. D Radware, MS Thesis, McGill University (2020).

ارتقاء امنیت وب با وف ایرانی