K. Baktybayev,
A. Dalelkhankyzy
Al-Farabi Kazakh National University, Almaty,
Kazakhstan
The
nucleon-pair model of collective excitation of nuclei
In this paper, we
again give a microscopic justification of the interacting
boson model (IBM) for the description of low-energy collective excitations of
the nucleon systems, and it is provided quite well by taking into account the S
and D-paired shell states in them. In addition, this allows to avoid the
well-known computational difficulties in the microscopic examination of the s
and d-bosons of IBM as the mappings of the S and D pairs of valence nucleons in
nuclei. As the mapping method of the fermion pair states in the boson the
Otsuki-Arima-Yakello (OAY) method is taken. In this SD-fermion pair model space
the Hamiltonian of the system is easily diagonalized and it satisfactorily
reproduces the spectra and electromagnetic transition probabilities of
vibrational, rotational, and 
unstable nuclei. Thus the microscopic phenomenological IBM is
constructed for the nuclear systems, the free parameters of the model are
calculated as the fermionic matrix elements of the pair forces of nucleon
interaction. On the other hand using the generalized quasispin formalism with
the pairing interaction of nucleon pairs some many-body effects are analyzed.
The theory is applied to studying the properties
of even spherical isotopes of 
. Their energy states are calculated in the main,
and 
bands as well
as the relative values of the reduced probabilities of electromagnetic
transitions and they are compared with experimental data.
References:
1. Takada K., Tazaki Sh., Yasumoto S. Dyson Boson Mapping and Shell-Model
Calculations of even-even Nuclei// Progr. Theor. Phys. 2006. Vol 16, ¹1. P.107.
2. Yan-An Luo et. Al. SD-pair shall model and the Interacting Boson model//
Phys. Rev. C71. 044304, 2005.
3. Yan-An Luo et. Al. // Phys. Rev. C71. 044304, 2005.
4. K. Baktybayev, A.Dalelkhankyzy, B. Ì.
Ê.Baktybayev //Adv. Studies Theor. Phys., Vol. 6, 1399-1404, 2012.