A RELATIVISTIC EFFECTIVE MODEL WITH PARAMETERIZED COUPLINGS FOR NEUTRON STARS

2011 ◽  
Vol 20 (supp01) ◽  
pp. 230-236
Author(s):  
AURORA PÉREZ MARTÍNEZ ◽  
HUGO PÉREZ ROJAS ◽  
DARYEL MANREZA PARET ◽  
ALEXANDRE MESQUITA ◽  
MOISÉS RAZEIRA ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Coupling Constants ◽  
The Other ◽  
Effective Model ◽  
Extended Model ◽  
Many Body ◽  
Parametric Dependence ◽  
Interaction Terms ◽  
Coupling Terms ◽  
Effective Models

We present a relativistic effective model with derivative couplings which includes genuine many-body forces simulated by nonlinear interaction terms involving scalar-isoscalar (σ, σ*), vector-isoscalar (ω, ɸ), vector-isovector (ϱ), scalar-isovector (δ) mesons. The effective model presented in this work has a philosophy quite similar to the original version of the model with parameterized couplings. But unlike that, in which the parametrization is directly inserted in the coupling constants of the Glendenning model, we present here a method for the derivation of the parametric dependence of the coupling terms, in a way that allows in one side to consistently justify this parametrization and in the other to extend in a coherent way the range of possibilities of parameterizations in effective models with derivative couplings. The extended model is then applied to the description of the mass of neutron stars.

A RELATIVISTIC EFFECTIVE MODEL WITH PARAMETERIZED COUPLINGS FOR NEUTRON STARS: THE ROLE OF ANTIKAON CONDENSATES

2011 ◽  
Vol 20 (supp02) ◽  
pp. 133-139
Author(s):  
ALEXANDRE MESQUITA ◽  
MOISÉS RAZEIRA ◽  
DIMITER HADJIMICHEF ◽  
CÉSAR A. Z. VASCONCELLOS ◽  
ROSANA O. GOMES ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Coupling Constants ◽  
Effective Model ◽  
Extended Model ◽  
Many Body ◽  
Parametric Dependence ◽  
Interaction Terms ◽  
Coupling Terms ◽  
Effective Models

We study the effects of antikaon condensates in neutron stars in the framework of a relativistic effective model with derivative couplings which includes genuine many-body forces simulated by nonlinear interaction terms involving scalar-isoscalar (σ, σ*), vector-isoscalar (ω, ɸ), vector-isovector (ϱ), scalar-isovector (δ) mesons. The effective model presented in this work has a philosophy quite similar to the original version of the model with parameterized couplings. But unlike that, in which the parametrization is directly inserted in the coupling constants of the Glendenning model, we present here a method for the derivation of the parametric dependence of the coupling terms, in a way that allows in one side to consistently justify this parametrization and in the other to extend in a coherent way the range of possibilities of parameterizations in effective models with derivative couplings. The extended model is then applied to the description of the mass of neutron stars.

GLUEBALL-DILATON AS AN ALTERNATIVE TO DARK MATTER IN NEUTRON STARS

2011 ◽  
Vol 20 (supp01) ◽  
pp. 281-287
Author(s):  
C. A. Z. VASCONCELLOS ◽  
A. MESQUITA ◽  
M. RAZEIRA ◽  
D. HADJIMICHEF ◽  
J. E. COSTA
Keyword(s):  
Dark Matter ◽  
Neutron Stars ◽  
Quantum Chromodynamics ◽  
Scale Invariance ◽  
Mean Field ◽  
Effective Model ◽  
Extended Version ◽  
Dilaton Field ◽  
Many Body ◽  
Interaction Terms

We study cold nuclear matter based on a mean field description of baryons bound by the exchange of scalar-isoscalar, vector-isoscalar, scalar-isovector and vector-isovector meson fields as well as the glueball field. For this task, we use an extended version of the effective model with derivative couplings with genuine many-body forces simulated by nonlinear self-couplings and meson-meson interaction terms involving scalar-isoscalar (σ, σ*), vector-isoscalar (ω, ɸ), vector-isovector (ϱ), scalar-isovector (δ) meson and the glueball fields. In our approach, the realization of the broken scale invariance of quantum chromodynamics is achieved through the introduction of a dilaton field. The effective model with dilatons is the applied to the description of neutron stars.

scholarly journals Highly Magnetized Neutron Stars in a Many-body Forces Formalism

2017 ◽  
Vol 45 ◽  
pp. 1760033
Author(s):  
Rosana O. Gomes ◽  
Cesar A. Z. Vasconcellos ◽  
Bruno Franzon ◽  
Stefan Schramm ◽  
Veronica Dexheimer
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Mean Field ◽  
Nuclear Interaction ◽  
Coupling Constants ◽  
Many Body ◽  
Poloidal Magnetic Field ◽  
Relativistic Mean Field ◽  
Body Forces ◽  
Consistent Solution

In this work, we study the effects of different magnetic field configurations in neutron stars described by a many-body forces formalism (MBF model). The MBF model is a relativistic mean field formalism that takes into account many-body forces by means of a meson field dependence of the nuclear interaction coupling constants. We choose the best parametrization of the model that reproduces nuclear matter properties at saturation and also describes massive neutron stars. We assume matter to be in beta-equilibrium, charge neutral and at zero temperature. Magnetic fields are taken into account both in the equation of state and in the structure of the stars by the self-consistent solution of the Einstein-Maxwell equations. We assume a poloidal magnetic field distribution and calculate its effects on neutron stars, showing its influence on the gravitational mass and deformation of the stars.

The Electron Effect of Aromatic Group: Control Conformation of 2-Aromatic Cyclododecanone Derivatives

2020 ◽  
Vol 24 (10) ◽  
pp. 1139-1147
Author(s):  
Yang Mingyan ◽  
Wang Daoquan ◽  
Wang Mingan
Keyword(s):  
1H Nmr ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
The Other ◽  
Repulsive Interaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Effect ◽  
Group Control

2-Phenylcyclododecanone and 2-cyclohexylcyclododecanone derivatives were synthesized and characterized by 1H NMR, 13C NMR, HR-ESI-MS and X-ray diffraction. Their preferred conformations were analyzed by the coupling constants in the 1H NMR spectra and X-ray diffraction, which showed the skeleton ring of these derivatives containing [3333]-2-one conformation, and the phenyl groups were located at the side-exo position of [3333]-2-one conformation due to the strong π-π repulsive interaction between the π- electron of benzene ring and π-electron of carbonyl group. The cyclohexyl groups were located at the corner-syn or the side-exo position of [3333]-2-one conformation depending on the hindrance of the other substituted groups. The π-π electron effect played a crucial role in efficiently controlling the preferred conformation of 2-aromatic cyclododecanone and the other 2-aromatic macrocyclic derivatives with the similar preferred square and rectangular conformations.

scholarly journals Nuclear Forces in High Density Matter

1971 ◽  
Vol 46 ◽  
pp. 356-363
Author(s):  
M. R. McNaughton
Keyword(s):  
Neutron Stars ◽  
Nuclear Physics ◽  
High Density ◽  
Exclusion Principle ◽  
Nuclear Forces ◽  
Many Body ◽  
Simple Method ◽  
Preliminary Results ◽  
Future Developments ◽  
Density Matter

The conditions for superfluidity or ferromagnetism in neutron stars are presented and discussed (but not derived). It is suggested that present estimates relating to these are in error and that the predictions made contradict at least one of three sets of nuclear physics data cited in the text. This is due to neglecting the action of the exclusion principle.A comparatively simple method for calculating the strength of nuclear forces in the presence of many-body effects is outlined. Some preliminary results are presented together with projected future developments.

An Atomistic Study of Ti Segregation to Lamellar Interfaces in Ti-RICH TiAl

1997 ◽  
Vol 492 ◽  
Author(s):  
K. Ito ◽  
V. Vitek
Keyword(s):  
The Other ◽  
Many Body ◽  
Monte Carlo Calculations ◽  
Narrow Region ◽  
Specific Distribution ◽  
Thin Region ◽  
Body Potential ◽  
Atomistic Study ◽  
Lamellar Interfaces ◽  
The Ideal

ABSTRACTIn this paper we analyze the effect of the surplus of titanium in the bulk on γ/γ interfaces. Monte Carlo calculations using a central force many-body potential suggest that in Ti rich alloys titanium segregates to the 120° rotational fault and the pseudotwin. This leads to the formation of a thin region of the DO19 Ti3Al at these interfaces. While titanium does not segregate to the ordered twin, it does to the ordered twin with the APB. But in this case the interface dissociates into the 120° rotational fault and the pseudotwin. The calculations further show that there are two types of atomic sites at the interfaces. One is the same as in the ideal L10 the other, to which the segregation takes place, is specific for interfaces parallel to {111} planes. The specific distribution of the sites favored for segregation is the reason why segregation leads to the formation of a narrow region of the DO19 Ti3Al in the 120° rotational fault and the pseudotwin.

THE ROLE OF THE NUCLEAR MATTER COMPRESSION MODULUS IN NEUTRON STARS

2004 ◽  
Vol 13 (07) ◽  
pp. 1519-1524 ◽  
Author(s):  
VERÔNICA A. DEXHEIMER ◽  
CÉSAR A. Z. VASCONCELLOS ◽  
MOISÉS RAZEIRA ◽  
MANFRED DILLIG
Keyword(s):  
Neutron Stars ◽  
Nuclear Matter ◽  
Body Problem ◽  
Mean Field Theory ◽  
Mean Field ◽  
Compression Modulus ◽  
Baryon Number ◽  
Many Body ◽  
Relativistic Mean Field

For the nuclear many body problem at high densities, formulated in the framework of a relativistic mean-field theory, we investigate in detail the compression modulus of nuclear matter as a function of the effective nucleon mass. We include consistently in our modelling chemical equilibrium as well as baryon number and electric charge conservation and investigate properties of neutron stars. Among other predictions we focus on the dependence of the maximum mass of a sequence of neutron stars as a function of the compression modulus and the nucleon effective mass.

NEUTRON STARS IN AN EFFECTIVE MODEL WITH ADJUSTABLE COEFFICIENTS

2010 ◽  
Author(s):  
A. MESQUITA ◽  
M. RAZEIRA ◽  
F. FERNÁNDEZ ◽  
C.A.Z. VASCONCELLOS
Keyword(s):  
Neutron Stars ◽  
Effective Model
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