EXOTIC ELECTROMAGNETIC TRANSITIONS IN NEUTRON-RICH CARBON ISOTOPES

2009 ◽  
Vol 18 (10) ◽  
pp. 1992-1996 ◽  
Author(s):  
TOSHIO SUZUKI ◽  
TAKAHARU OTSUKA

Structure and electromagnetic properties of exotic neutron-rich carbon isotopes are studied by shell model calculations. A p-sd shell model Hamiltonian is modified by enhancing the effects of the tensor force in the p-sd cross shell matrix elements as well as with corrections in the T=1 monopole terms. A considerable suppression of the magnetic dipole (M1) transition in 17 C from the [Formula: see text] state recently observed is found to be well explained by the modified Hamiltonian. The anomalous hindrance of the quadrupole (E2) transitions in 16 C and 18 C is also shown to be reproduced by our new Hamiltonian.

2021 ◽  
Vol 66 (4) ◽  
pp. 293
Author(s):  
A.A. Al-Sammarraie ◽  
F.A. Ahmed ◽  
A.A. Okhunov

The negative-parity states of 24Mg nucleus are investigated within the shell model. We are based on the calculations of energy levels, total squared form factors, and transition probability using the p-sd-pf (PSDPF) Hamiltonian in a large model space (0 + 1) hW. The comparison between the experimental and theoretical states showed a good agreement within a truncated model space. The PSDPF-based calculations successfully reproduced the data on the total squared form factors and transition probabilities of the negative-parity states in 24Mg nucleus. These quantities depend on the one-body density matrix elements that are obtained from the PSDPF Hamiltonian. The wave functions of radial one-particle matrix elements calculated with the harmonic-oscillator potential are suitable to predict experimental data by changing the center-of-mass corrections.


2007 ◽  
Vol 16 (02) ◽  
pp. 552-560 ◽  
Author(s):  
E. CAURIER ◽  
F. NOWACKI ◽  
A. POVES

The determination of accurate nuclear matrix elements for ββ decay processes is a challenge for nuclear theory and can have a strong impact in neutrino physics. Large Scale Shell Model (LSSM) calculations are among the best tools for such determination and recent developments have allowed to extend its application domains. In particular, systematic studies of nuclear matrix elements calculations have been now undertaken in this framework for most of the ββ emitters. These calculations are crucial in the determination of the most favorable emitters in the forthcoming generation of ββ experiments. The present paper focuses on the recent advances and remaining difficulties of shell model calculations for the neutrinoless mode. Stability and predictive power of the results will be discussed.


1982 ◽  
Vol 26 (5) ◽  
pp. 2247-2272 ◽  
Author(s):  
B. A. Brown ◽  
B. H. Wildenthal ◽  
W. Chung ◽  
S. E. Massen ◽  
M. Bernas ◽  
...  

2019 ◽  
Vol 64 (19) ◽  
pp. 2037-2042
Author(s):  
Yifang Geng ◽  
Yuanzhuo Ma ◽  
Jianguo Li ◽  
Furong Xu

2020 ◽  
Vol 1 ◽  
pp. 156
Author(s):  
J. Sinatkas ◽  
L. D. Skouras ◽  
D. Strottman ◽  
J. D. Vergados

The structure of the Ζ,Ν < 50 nuclei is examined in a model space consisting of the 0g9/2, 1p1/2, 1p3/2 and the 0f5/2 hole orbitals outside the doubly closed 100Sn core. The effective interaction for this model space is derived by introducing second order corrections to the Sussex matrix elements, while the one-hole energies are deduced by a least square fit to the observed levels. The results of the calculation are found to be in very satisfactory agreement with experiment for all nuclei with 38<Ζ<46 but for Ζ<38 this agreement begins to deteriorate. Such a feature possibly indicates the appearance of deformation and the breaking of the Ν=50 core. The wavefunctions of the calculation are used to determine double β matrix elements in the Ge, Se, Sr and Kr isotopes.


2018 ◽  
Vol 194 ◽  
pp. 02005
Author(s):  
Hiroyuki Sagawa ◽  
Toshio Suzuki

We study the spin magnetic dipole transitions in sd-shell even-even nuclei with N=Z and a p-shell nucleus 12C by modern shell model calculations. The shell model wave functions take into account enhanced isoscalar (IS) spin-triplet pairing as well as the effective spin operators. We point out that the IS pairing and the effective spin operators give a large quenching effect on the isovector (IV) spin transitions to be consistent with observed data by (p, p′) experiments. On the other hand, the observed IS spin strengths do not show large quenching effect suggested by the calculated investigation. The IS pairing gives a substantial quenching effect on the spin magnetic dipole transitions, especially on the IV ones.


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