scholarly journals Explanation for why the early universe was stable and dominated by the standard model

2020 ◽  
Vol 2020 (12) ◽  
pp. 025-025
Author(s):  
Mark P. Hertzberg ◽  
Mudit Jain
Keyword(s):  
Standard Model ◽  
Early Universe ◽  
The Standard Model

scholarly journals Sterile Neutrinos as Dark Matter: Alternative Production Mechanisms in the Early Universe

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 264
Author(s):  
Daniel Boyanovsky
Keyword(s):  
Dark Matter ◽  
Distribution Function ◽  
Kinetic Equation ◽  
Standard Model ◽  
Early Universe ◽  
Quantum Kinetic Equation ◽  
Sterile Neutrinos ◽  
The Standard Model ◽  
Production Mechanisms ◽  
Freeze Out

We study various production mechanisms of sterile neutrinos in the early universe beyond and within the standard model. We obtain the quantum kinetic equations for production and the distribution function of sterile-like neutrinos at freeze-out, from which we obtain free streaming lengths, equations of state and coarse grained phase space densities. In a simple extension beyond the standard model, in which neutrinos are Yukawa coupled to a Higgs-like scalar, we derive and solve the quantum kinetic equation for sterile production and analyze the freeze-out conditions and clustering properties of this dark matter constituent. We argue that in the mass basis, standard model processes that produce active neutrinos also yield sterile-like neutrinos, leading to various possible production channels. Hence, the final distribution function of sterile-like neutrinos is a result of the various kinematically allowed production processes in the early universe. As an explicit example, we consider production of light sterile neutrinos from pion decay after the QCD phase transition, obtaining the quantum kinetic equation and the distribution function at freeze-out. A sterile-like neutrino with a mass in the keV range produced by this process is a suitable warm dark matter candidate with a free-streaming length of the order of few kpc consistent with cores in dwarf galaxies.

scholarly journals Relativistic Cosmology with an Introduction to Inflation

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 276
Author(s):  
Muhammad Zahid Mughal ◽  
Iftikhar Ahmad ◽  
Juan Luis García Guirao
Keyword(s):  
Standard Model ◽  
Early Universe ◽  
Large Scale ◽  
Initial Conditions ◽  
Big Bang ◽  
Relativistic Cosmology ◽  
The Standard Model ◽  
Big Bang Model ◽  
The Big Bang ◽  
The Universe

In this review article, the study of the development of relativistic cosmology and the introduction of inflation in it as an exponentially expanding early phase of the universe is carried out. We study the properties of the standard cosmological model developed in the framework of relativistic cosmology and the geometric structure of spacetime connected coherently with it. The geometric properties of space and spacetime ingrained into the standard model of cosmology are investigated in addition. The big bang model of the beginning of the universe is based on the standard model which succumbed to failure in explaining the flatness and the large-scale homogeneity of the universe as demonstrated by observational evidence. These cosmological problems were resolved by introducing a brief acceleratedly expanding phase in the very early universe known as inflation. The cosmic inflation by setting the initial conditions of the standard big bang model resolves these problems of the theory. We discuss how the inflationary paradigm solves these problems by proposing the fast expansion period in the early universe. Further inflation and dark energy in fR modified gravity are also reviewed.

scholarly journals On catalyzed vacuum decay around a radiating black hole and the crisis of the electroweak vacuum

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Takumi Hayashi ◽  
Kohei Kamada ◽  
Naritaka Oshita ◽  
Jun’ichi Yokoyama
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Standard Model ◽  
Decay Rate ◽  
Early Universe ◽  
Hawking Radiation ◽  
False Vacuum ◽  
Vacuum Decay ◽  
Higgs Vacuum ◽  
The Standard Model

Abstract False vacuum decay is a key feature in quantum field theories and exhibits a distinct signature in the early Universe cosmology. It has recently been suggested that the false vacuum decay is catalyzed by a black hole (BH), which might cause the catastrophe of the Standard Model Higgs vacuum if primordial BHs are formed in the early Universe. We investigate vacuum phase transition of a scalar field around a radiating BH with taking into account the effect of Hawking radiation. We find that the vacuum decay rate slightly decreases in the presence of the thermal effect since the scalar potential is stabilized near the horizon. However, the stabilization effect becomes weak at the points sufficiently far from the horizon. Consequently, we find that the decay rate is not significantly changed unless the effective coupling constant of the scalar field to the radiation is extremely large. This implies that the change of the potential from the Hawking radiation does not help prevent the Standard Model Higgs vacuum decay catalyzed by a BH.

scholarly journals Cosmological Synthesis of the Elements

1974 ◽  
Vol 63 ◽  
pp. 195-210
Author(s):  
Robert V. Wagoner
Keyword(s):  
Standard Model ◽  
Early Universe ◽  
Big Bang ◽  
Statistical Bootstrap ◽  
The Standard Model ◽  
Bootstrap Theory

The results of improved calculations of the abundances of the nuclei produced in big-bang models of the early universe are presented. In addition to the standard model, other possible universes are considered, including the recent statistical bootstrap theory of Carlitz, Frautschi, and Nahm. Some conclusions which can be drawn about the nature of the early universe, depending upon whether the observed deuterium and helium are of galactic or cosmological origin, are presented.

scholarly journals Primordial Nucleosynthesis For The New Millennium

2000 ◽  
Vol 198 ◽  
pp. 13-24
Author(s):  
G. Steigman
Keyword(s):  
Standard Model ◽  
Early Universe ◽  
Particle Physics ◽  
Nuclear Reactor ◽  
Big Bang ◽  
Status Report ◽  
Primordial Nucleosynthesis ◽  
The Road ◽  
The Standard Model ◽  
Primordial Abundance

The physics of the standard hot big bang cosmology ensures that the early Universe was a primordial nuclear reactor, synthesizing the light nuclides (D, 3He, 4He, and 7Li) in the first 20 minutes of its evolution. After an overview of nucleosynthesis in the standard model (SBBN), the primordial abundance yields will be presented, followed by a status report (intended to stimulate further discussion during this symposium) on the progress along the road from observational data to inferred primordial abundances. Theory will be confronted with observations to assess the consistency of SBBN and to constrain cosmology and particle physics. Some of the issues/problems key to SBBN in the new millenium will be highlighted, along with a wish list to challenge theorists and observers alike.

scholarly journals Predictions for axion couplings from ALP cogenesis

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Raymond T. Co ◽  
Lawrence J. Hall ◽  
Keisuke Harigaya
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Early Universe ◽  
Decay Constant ◽  
Stellar Objects ◽  
The Standard Model ◽  
Field Velocity

Abstract Adding an axion-like particle (ALP) to the Standard Model, with a field velocity in the early universe, simultaneously explains the observed baryon and dark matter densities. This requires one or more couplings between the ALP and photons, nucleons, and/or electrons that are predicted as functions of the ALP mass. These predictions arise because the ratio of dark matter to baryon densities is independent of the ALP field velocity, allowing a correlation between the ALP mass, ma, and decay constant, fa. The predicted couplings are orders of magnitude larger than those for the QCD axion and for dark matter from the conventional ALP misalignment mechanism. As a result, this scheme, ALP cogenesis, is within reach of future experimental ALP searches from the lab and stellar objects, and for dark matter.

scholarly journals Kaluza-Klein FIMP dark matter in warped extra-dimensions

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Nicolás Bernal ◽  
Andrea Donini ◽  
Miguel G. Folgado ◽  
Nuria Rius
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Early Universe ◽  
Extra Dimensions ◽  
The Standard Model ◽  
Massive Particles ◽  
Warped Extra Dimensions ◽  
Relic Abundance ◽  
First Time ◽  
Kaluza Klein

Abstract We study for the first time the case in which Dark Matter (DM) is made of Feebly Interacting Massive Particles (FIMP) interacting just gravitationally with the standard model particles in an extra-dimensional Randall-Sundrum scenario. We assume that both the dark matter and the standard model are localized in the IR-brane and only interact via gravitational mediators, namely the graviton, the Kaluza-Klein gravitons and the radion. We found that in the early Universe DM could be generated via two main processes: the direct freeze-in and the sequential freeze-in. The regions where the observed DM relic abundance is produced are largely compatible with cosmological and collider bounds.

scholarly journals The Higgs Field and Early Universe Cosmology: A (Brief) Review

Physics ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 503-520
Author(s):  
Bart Horn
Keyword(s):  
Standard Model ◽  
Recent Work ◽  
Early Universe ◽  
Higgs Field ◽  
Scalar Fields ◽  
The Standard Model ◽  
Early Universe Cosmology ◽  
Selection Mechanisms ◽  
The Universe

We review and discuss recent work exploring the implications of the Higgs field for early universe cosmology, and vice versa. Depending on the model under consideration, the Higgs may be one of a few scalar fields determining the evolution and fate of the Universe, or the Higgs field may be connected to a rich sector of scalar moduli with complicated dynamics. In particular, we look at the potential consequences of the Higgs field for inflation and its predictions, for the (meta)stability of the Standard Model vacuum, and for the existence of dynamical selection mechanisms in the landscape.

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