Nuclear Theory·nucl-th

Wednesday·January 13, 2016

8 papers—5 primary·3 cross-listed

01
[Submitted on 12 Jan 2016]
Symmetries and deformations in the spherical shell model
Piet Van Isacker🇫🇷 · Stuart Pittel🇺🇸
We discuss symmetries of the spherical shell model that make contact with the geometric collective model of Bohr and Mottelson. The most celebrated symmetry of this kind is SU(3), which is the basis of Elliott's model of rotation. It corresponds to a deformed mean field induced by a quadrupole interaction in a single major oscillator shell N and can be generalized to include several major shells. As such, Elliott's SU(3) model establishes the link between the spherical shell model and the (quadrupole component of the) geometric collective model. We introduce the analogue symmetry induced by an octupole interaction in two major oscillator shells N-1 and N, leading to an octupole-deformed solution of the spherical shell model. We show that in the limit of large oscillator shells (large N) the algebraic octupole interaction tends to that of the geometric collective model.
Comments:
23 pages, 7 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1601.02837 [pdf]
Phys.Scripta(2016)·22 citations
02
[Submitted on 27 Nov 2015]
Influence of the weakly interacting light U boson on the properties of massive PNS
Bin Hong · Huan-Yu Jia · Xia Zhou · Xue-Ling Mu
Considering the octet baryons in relativistic mean field theory and selecting entropy per baryon S=1, we calculate and discuss the influence of U boson on the equation of state, mass-radius, moment of inertia and gravitational redshift of massive protoneutron star (PNS). The effective coupling constant $g_{U}$ of U bosons and nucleons is selected from 0GeV $^{- 2}$ to 70GeV $^{- 2}$ . The results point that U bosons will stiffen the equation of state (EOS). The influence of U bosons on the pressure is more obvious at low density than high density, while, the influence of U bosons on the energy density is more obvious at high density than low density. The U bosons play a significant role in increasing the maximum mass and radius of PNS. When the value of $g_{U}$ changes from 0GeV $^{- 2}$ to 70GeV $^{- 2}$ , the maximum mass of massive PNS increases from 2.11 $M_{⊙}$ to 2.58 $M_{⊙}$ , and the radius of PNS corresponding PSR J0348+0432 increases from 13.71 km to 24.35 km. The U bosons will increase the moment of inertia and decrease the gravitational redshift of PNS. For PNS of the massive PSR J0348+0432, the radius and moment of inertia vary directly with $g_{U}$ , the gravitational redshift vary inversely with $g_{U}$ approximately.
Comments:
7 pages,7 figures,1 table
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
1601.02850 [pdf]
CPC(2016)·2 citations
03
[Submitted on 6 Jan 2016]
On the emission of the fast $δ -$ electrons during nuclear $β^{-}$ -decay in few-electron atoms
Alexei M. Frolov
We discuss a possibility to observe fast secondary electrons ( $δ -$ electrons) during nuclear $β^{-}$ -decay in few-electron atoms and ions. Formulas for the corresponding probabilities and explicit expression for the energy spectrum of $δ -$ electrons are derived in the closed analytical forms.
Subjects:
Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
1601.02855 [pdf]
EPL(2016)·0 citations
04
[Submitted on 8 Jan 2016]
Thermal evolution of hybrid stars within the framework of a nonlocal Nambu--Jona-Lasinio model
S. M. de Carvalho🇧🇷 · R. Negreiros🇧🇷 · M. Orsaria🇦🇷 · G. A. Contrera🇦🇷 · F. Weber🇺🇸 · W. Spinella🇺🇸
We study the thermal evolution of neutron stars containing deconfined quark matter in their core. Such objects are generally referred to as quark-hybrid stars. The confined hadronic matter in their core is described in the framework of non-linear relativistic nuclear field theory. For the quark phase we use a non-local extension of the SU(3) Nambu Jona-Lasinio model with vector interactions. The Gibbs condition is used to model phase equilibrium between confined hadronic matter and deconfined quark matter. Our study indicates that high-mass neutron stars may contain between 35 and 40 % deconfined quark-hybrid matter in their cores. Neutron stars with canonical masses of around $1.4 M_{⊙}$ would not contain deconfined quark matter. The central proton fractions of the stars are found to be high, enabling them to cool rapidly. Very good agreement with the temperature evolution established for the neutron star in Cassiopeia A (Cas A) is obtained for one of our models (based on the popular NL3 nuclear parametrization), if the protons in the core of our stellar models are strongly paired, the repulsion among the quarks is mildly repulsive, and the mass of Cas A has a canonical value of $1.4 M_{⊙}$ .
Comments:
10 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1601.02938 [pdf]
PRC(2015)·27 citations
05
[Submitted on 12 Jan 2016]
Partial wave decomposition of finite-range effective tensor interaction
D. Davesne🇫🇷 · P. Becker🇫🇷 · A. Pastore🇬🇧 · J. Navarro🇪🇸
We perform a detailed analysis of the properties of the finite-range tensor term associated with the Gogny and M3Y effective interactions. In particular, by using a partial wave decomposition of the equation of state of symmetric nuclear matter, we show how we can extract their tensor parameters directly from microscopic results based on bare nucleon-nucleon interactions. Furthermore, we show that the zero-range limit of both finite-range interactions has the form of the N3LO Skyrme pseudo-potential, which thus constitutes a reliable approximation in the density range relevant for finite nuclei. Finally, we use Brueckner-Hartree-Fock results to fix the tensor parameters for the three effective interactions.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1601.02956 [pdf]
PRC(2016)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE

Symmetries and deformations in the spherical shell model

Influence of the weakly interacting light U boson on the properties of massive PNS

On the emission of the fast δ−electrons during nuclear β−-decay in few-electron atoms

Thermal evolution of hybrid stars within the framework of a nonlocal Nambu--Jona-Lasinio model

Partial wave decomposition of finite-range effective tensor interaction

Affiliations

On the emission of the fast $δ -$ electrons during nuclear $β^{-}$ -decay in few-electron atoms