Superdeformation in theN=ZNucleus36Ar: Experimental, Deformed Mean Field, and Spherical Shell Model Descriptions

2000 ◽  
Vol 85 (13) ◽  
pp. 2693-2696 ◽  
Author(s):  
C. E. Svensson ◽  
A. O. Macchiavelli ◽  
A. Juodagalvis ◽  
A. Poves ◽  
I. Ragnarsson ◽  
...  
Keyword(s):  
Spherical Shell ◽  
Shell Model ◽  
Mean Field

WHY ARE SOME NUCLEI SPHERICAL?

1993 ◽  
Vol 02 (supp01) ◽  
pp. 71-79 ◽  
Author(s):  
KRISHNA KUMAR
Keyword(s):  
Potential Energy ◽  
Spherical Shell ◽  
Shell Model ◽  
Energy Minimization ◽  
Zero Point ◽  
Natural State ◽  
Atomic Nuclei ◽  
Point Motion ◽  
Spherical Nuclei ◽  
General Conditions

Energy minimization is not sufficient to determine whether a nucleus is spherical or deformed. The quantal zero-point motion can make a nucleus spherical even if the potential energy has a deformed minimum. However, some general conditions give deformed shape as the natural state of atomic nuclei. They are spherical only under some special conditions. Some general criteria for distinguishing spherical nuclei from deformed, as well as some advantages of using a deformed-shell model rather than a spherical-shell model, are presented.

scholarly journals Convection and Dynamo in Newly Born Neutron Stars

2022 ◽  
Vol 924 (2) ◽  
pp. 75
Author(s):  
Youhei Masada ◽  
Tomoya Takiwaki ◽  
Kei Kotake
Keyword(s):  
Spherical Shell ◽  
Neutron Stars ◽  
Large Scale ◽  
Convection Zone ◽  
Turbulent Transport ◽  
Mean Field ◽  
Magnetic Component ◽  
Large Scale Structures ◽  
Scale Structures ◽  
Convective Model

Abstract To study properties of magnetohydrodynamic (MHD) convection and resultant dynamo activities in proto-neutron stars (PNSs), we construct a “PNS in a box” simulation model and solve the compressible MHD equation coupled with a nuclear equation of state (EOS) and simplified leptonic transport. As a demonstration, we apply it to two types of PNS model with different internal structures: a fully convective model and a spherical-shell convection model. By varying the spin rate of the models, the rotational dependence of convection and the dynamo that operate inside the PNS is investigated. We find that, as a consequence of turbulent transport by rotating stratified convection, large-scale structures of flow and thermodynamic fields are developed in all models. Depending on the spin rate and the depth of the convection zone, various profiles of the large-scale structures are obtained, which can be physically understood as steady-state solutions to the “mean-field” equation of motion. Additionally to those hydrodynamic structures, a large-scale magnetic component of  ( 10 15 ) G is also spontaneously organized in disordered tangled magnetic fields in all models. The higher the spin rate, the stronger the large-scale magnetic component grows. Intriguingly, as an overall trend, the fully convective models have a stronger large-scale magnetic component than that in the spherical-shell convection models. The deeper the convection zone extends, the larger the size of the convective eddies becomes. As a result, rotationally constrained convection seems to be more easily achieved in the fully convective model, resulting in a higher efficiency of the large-scale dynamo there. To gain a better understanding of the origin of the diversity of a neutron star’s magnetic field, we need to study the PNS dynamo in a wider parameter range.

Gamow–Teller strength functions from scattering experiments

1987 ◽  
Vol 65 (6) ◽  
pp. 691-698 ◽  
Author(s):  
O. Häusser
Keyword(s):  
Shell Model ◽  
Cross Sections ◽  
Mean Field ◽  
Wave Functions ◽  
Structure Information ◽  
Model Wave ◽  
Spin Flip ◽  
Strength Functions ◽  
Gamow Teller ◽  
Good Agreement

We present here recent [Formula: see text] results from TRIUMF that are relevant to the determination of spin-flip isovector strength functions in nuclei. Distortion factors needed for the extraction of nuclear-structure information have been deduced from cross sections and analyzing powers in elastic scattering for several energies and targets. Nonrelativistic optical potentials obtained by folding effective nucleon (N)–nucleus interactions with nuclear densities are found to overpredict both elastic and reaction cross sections, whereas Dirac calculations that include Pauli blocking are in good agreement with the data. Spin observables (Snn and Ay) for the quasi-elastic region in 54Fe[Formula: see text] at 290 MeV provide some evidence for the reduction of the effective proton mass predicted in relativistic mean-field theories as a consequence of the attractive scalar field in the nuclear medium. The energy dependence of the effective N–nucleus interaction at small momentum transfers has been investigated using isoscalar and isovector 1+ states in 28Si as probe states. We find that the cross sections for the isovector transitions are in good agreement with predictions for the dominant Vστ part of the Franey–Love interaction. Gamow–Teller (GT) strength functions have been obtained in 24Mg and 54Fe from measurements of both cross sections and spin–flip probabilities Snn. The spin-flip cross sections σSnn are particularly useful in heavier nuclei to discriminate against a continuous background of ΔS = 0 excitations. In the (s, d) shell where full shell-model wave functions are available, the GT quenching factors [Formula: see text] are in good agreement with those from recent (p, n) and (n, p) experiments. We show that a state-by-state comparison of (p, p′) and (e, e′) results has the potential of identifying pionic current contributions in (e, e′). The GT quenching factors in 54Fe are smaller than in the (s, d) shell probably because of severely truncated shell-model wave functions, particularly those of the nuclear ground state.

Shell model and mean-field description of band termination in theA∼44 nuclei

2007 ◽  
Vol 75 (5) ◽  
Author(s):  
M. Zalewski ◽  
W. Satuła ◽  
W. Nazarewicz ◽  
G. Stoitcheva ◽  
H. Zduńczuk
Keyword(s):  
Shell Model ◽  
Mean Field ◽  
Band Termination

Dielectric properties of nucleated erythrocytes as simulated by the double spherical-shell model

2020 ◽  
Vol 29 (12) ◽  
pp. 128703
Author(s):  
Jia Xu ◽  
Weizhen Xie ◽  
Yiyong Chen ◽  
Lihong Wang ◽  
Qing Ma
Keyword(s):  
Dielectric Properties ◽  
Spherical Shell ◽  
Shell Model
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