scholarly journals Hyperons: the strange ingredients of the nuclear equation of state

2018 ◽  
Vol 474 (2217) ◽  
pp. 20180145 ◽  
Author(s):  
Isaac Vidaña
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Weak Decay ◽  
Effective Field ◽  
Meson Exchange ◽  
Decay Modes ◽  
Nuclear Equation Of State ◽  
Nuclear Systems ◽  
Consequent Reduction ◽  
Recent Developments

We review the role and properties of hyperons in finite and infinite nuclear systems. In particular, we present different production mechanisms of hypernuclei, as well as several aspects of hypernuclear γ -ray spectroscopy, and the weak decay modes of hypernuclei. Then we discuss the construction of hyperon–nucleon and hyperon–hyperon interactions on the basis of the meson-exchange and chiral effective field theories. Recent developments based on the so-called V low  k approach and lattice quantum chromodynamics will also be addressed. Finally, we go over some of the effects of hyperons on the properties of neutron and proto-neutron stars with an emphasis on the so-called ‘hyperon puzzle’, i.e. the problem of the strong softening of the equation of state, and the consequent reduction of the maximum mass, induced by the presence of hyperons, a problem which has become more intriguing and difficult to solve due the recent measurements of approximately 2 M ⊙ millisecond pulsars. We discuss some of the solutions proposed to tackle this problem. We also re-examine the role of hyperons on the cooling properties of newly born neutron stars and on the development of the so-called r-mode instability.

scholarly journals Chiral Effective Field Theory and the High-Density Nuclear Equation of State

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
C. Drischler ◽  
J.W. Holt ◽  
C. Wellenhofer
Keyword(s):  
Field Theory ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Effective Field Theory ◽  
Effective Field ◽  
High Density ◽  
Chiral Effective Field Theory ◽  
Nuclear Equation Of State ◽  
Density Regime

Born in the aftermath of core-collapse supernovae, neutron stars contain matter under extraordinary conditions of density and temperature that are difficult to reproduce in the laboratory. In recent years, neutron star observations have begun to yield novel insights into the nature of strongly interacting matter in the high-density regime where current theoretical models are challenged. At the same time, chiral effective field theory has developed into a powerful framework to study nuclear matter properties with quantified uncertainties in the moderate-density regime for modeling neutron stars. In this article, we review recent developments in chiral effective field theory and focus on many-body perturbation theory as a computationally efficient tool for calculating the properties of hot and dense nuclear matter. We also demonstrate how effective field theory enables statistically meaningful comparisons among nuclear theory predictions, nuclear experiments, and observational constraints on the nuclear equation of state. Expected final online publication date for the Annual Review of Nuclear and Particle Science, Volume 71 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Hyperons in Finite and Infinite Nuclear Systems

Universe ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 376
Author(s):  
Isaac Vidaña
Keyword(s):  
Neutron Stars ◽  
Weak Decay ◽  
Theoretical Description ◽  
Mode Instability ◽  
Decay Modes ◽  
Nuclear Systems ◽  
Γ Ray ◽  
Production Mechanisms

In this work, we shortly review the role and properties of hyperons in finite and infinite nuclear systems such as hypernuclei and neutron stars. Particularly, we describe different production mechanisms of hypernuclei, discuss some aspects of their γ-ray spectroscopy and their weak decay modes, and give a few strokes on their theoretical description. We reexamine also the role played by hyperons on the properties of neutron and proto-neutron stars with a special emphasis on the well-known “hyperon puzzle”, of which we discuss some of the solutions that have been proposed to tackle this problem. Finally, we review the role of hyperons on the cooling properties of newly born neutron stars and on the so-called r-mode instability.

scholarly journals Nuclear equation of state and neutron star cooling

2017 ◽  
Vol 26 (04) ◽  
pp. 1750015 ◽  
Author(s):  
Yeunhwan Lim ◽  
Chang Ho Hyun ◽  
Chang-Hwan Lee
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Thermal Evolution ◽  
Observation Data ◽  
Nuclear Equation Of State ◽  
The Core ◽  
Dense Nuclear Matter ◽  
Nuclear Models

In this paper, we investigate the cooling of neutron stars with relativistic and nonrelativistic models of dense nuclear matter. We focus on the effects of uncertainties originated from the nuclear models, the composition of elements in the envelope region, and the formation of superfluidity in the core and the crust of neutron stars. Discovery of [Formula: see text] neutron stars PSR J1614−2230 and PSR J0343[Formula: see text]0432 has triggered the revival of stiff nuclear equation of state at high densities. In the meantime, observation of a neutron star in Cassiopeia A for more than 10 years has provided us with very accurate data for the thermal evolution of neutron stars. Both mass and temperature of neutron stars depend critically on the equation of state of nuclear matter, so we first search for nuclear models that satisfy the constraints from mass and temperature simultaneously within a reasonable range. With selected models, we explore the effects of element composition in the envelope region, and the existence of superfluidity in the core and the crust of neutron stars. Due to uncertainty in the composition of particles in the envelope region, we obtain a range of cooling curves that can cover substantial region of observation data.

scholarly journals How neutron stars constrain the nuclear equation of state

2014 ◽  
Vol 66 ◽  
pp. 04011
Author(s):  
Thomas Hell ◽  
Bernhard Röttgers ◽  
Wolfram Weise
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Equation Of State

THE BETHE–BRUECKNER–GOLDTONE THEORY OF THE NUCLEAR EQUATION OF STATE AND NEUTRON STARS

2003 ◽  
Vol 17 (28) ◽  
pp. 5127-5137 ◽  
Author(s):  
M. BALDO ◽  
G. F. BURGIO
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Gluon Plasma ◽  
Many Body ◽  
Static Properties ◽  
Many Body Theory ◽  
Nuclear Equation Of State ◽  
Pure Neutron Matter ◽  
Particle Potential ◽  
Three Body

The microscopic many-body theory of the Nuclear Equation of State is discussed in the framework of the Bethe–Brueckner–Goldstone method. The expansion is extended up to the three hole-line diagrams contribution. The Brueckner equation for the two-body G-matrix and the Bethe–Fadeev equation for the three-body scattering matrix are solved both for the gap and continuous choices of the single particle potential. For symmetric and pure neutron matter strong evidence of convergence in the expansion is found. Once three-body forces are introduced, the phenomenological saturation point is reproduced. In order to study neutron stars static properties, the theory is extended to include strangeness, and the possible quark-gluon plasma component is described in the simplified MIT bag model. The results for the mass and radius of neutron stars are briefly discussed.

scholarly journals Rotation-Driven Phase Transitions in the Cores of Pulsars

2017 ◽  
Vol 45 ◽  
pp. 1760035
Author(s):  
Richard D. Mellinger ◽  
William Spinella ◽  
Fridolin Weber ◽  
Gustavo A. Contrera ◽  
Milva Orsaria
Keyword(s):  
Phase Transitions ◽  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Quark Matter ◽  
Nuclear Data ◽  
Particle Composition ◽  
Nuclear Equation Of State ◽  
The Impact ◽  
Gravitational Compression

In this paper, we discuss the impact of rotation on the particle composition of rotating neutron stars (pulsars). Particular emphasis is put on the formation of quark matter during stellar spin-down, driven by continuous gravitational compression. Our study is based on modern models for the nuclear equation of state whose parameters are tightly constrained by nuclear data, neutron star masses, and the latest estimates of neutron star radii.

scholarly journals New Constraints on the Nuclear Equation of State from the Thermal Emission of Neutron Stars in Quiescent Low-mass X-Ray Binaries

2019 ◽  
Vol 887 (1) ◽  
pp. 48 ◽  
Author(s):  
Nicolas Baillot d’Etivaux ◽  
Sebastien Guillot ◽  
Jérôme Margueron ◽  
Natalie Webb ◽  
Márcio Catelan ◽  
...  
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Thermal Emission ◽  
X Ray ◽  
Nuclear Equation Of State ◽  
Low Mass ◽  
X Ray Binaries
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