RI Physics Seminar：The g_9/2 orbital and structure of neutron-rich Cr and Fe nuclei
by
DrYang SUN(Shanghai Jiao Tong University)
→
Asia/Tokyo
Description
Recent experimental data have reached the high-spin region in some neutron-rich chromium and iron isotopes near N=40. The high-spin data contain more useful information, which suggests an increasing importance of the neutron g_9/2 orbital for these nuclei. The most direct evidence of the g_9/2 orbital is that in the odd-mass isotopes, the first excited 9/2^+ state drops down rapidly when neutrons are added. The low-spin states, i.e. the 2^+ level in even-even nuclei, and sometimes the 4^+ level as well, can be well reproduced by large-scale shell model calculations. However, a proper description for the high-spin states of both positive- and negative-parity bands is more challenging.
We have applied the Projected Shell Model to study low- and high-spin states for even-even and odd-mass Cr and Fe isotopes [1,2,3]. We show that with increasing neutron number, evolution of shell gaps, shape changes, variation in high-spin levels and B(E2)'s, the high-K isomeric states, etc, are related to the g_9/2 physics. We explain how a system with a soft core near the ground state stabilizes the shape with the aid of rotation. As the discussion is based crucially on the deformed single-particle scheme, we emphasize that any future experimental confirmation or refutation of our predictions will be valuable information, which can help to pin down the single-particle structure in this neutron-rich mass region.
Some other theoretical projects that are carried out in our group will also be mentioned.
[1] Y. Sun, Y.-C. Yang, H.-L. Liu, K. Kaneko, M. Hasegawa, T. Mizusaki, Phys. Rev. C 80 (2009) 054306.
[2] Y.-C. Yang, Y. Sun, K. Kaneko, M. Hasegawa, Phys. Rev. C 82 (2010) 031304(R).
[3] Y.-C. Yang, H. Jin, Y. Sun, K. Kaneko, Phys. Lett. B 700 (2011) 44.