A COMMON SCENARIO LEADING TO A SMALL VACUUM ENERGY AND STABLE SUPER-MASSIVE PARTICLES

2013 ◽  
Vol 28 (27) ◽  
pp. 1350099 ◽  
Author(s):  
OSVALDO P. SANTILLÁN
Keyword(s):  
Vacuum Energy ◽  
Goldstone Boson ◽  
Heavy Particles ◽  
Hidden Sector ◽  
Mean Lifetime ◽  
The Standard Model ◽  
Present Universe ◽  
Age Of The Universe ◽  
The One ◽  
The Universe

A toy model giving rise to long-lived super-heavy particles and a small vacuum density energy, of the order of the one measured in the present universe, is presented. It consists in a hidden sector, invariant under an SU(2) gauge symmetry, with some masses provided by a specific double Higgs mechanism. It is assumed that the Standard Model particles are also charged under the SU(2) interaction, which is weak enough to allow super-heavy particles with mean lifetime with values larger than the age of the universe. The hidden fermions and the hidden Higgs are super-heavy, which mass values close to the GUT scale. In addition, there is a spontaneously broken U(1) chiral symmetry, giving rise to a pseudoscalar Goldstone boson which we refer as a "hidden axion". The vacuum energy of the universe is identified as the potential energy of this pseudoscalar.

scholarly journals Revisiting the decoupling effects in the running of the Cosmological Constant

2018 ◽  
Vol 33 (34) ◽  
pp. 1845013
Author(s):  
Oleg Antipin ◽  
Blaženka Melić
Keyword(s):  
Cosmological Constant ◽  
Higgs Mass ◽  
Vacuum Energy ◽  
Fine Tuning ◽  
Simple Extension ◽  
Heavy Particles ◽  
Entire Energy Range ◽  
The Standard Model ◽  
Entire Energy ◽  
Mass Dependent

We revisit the decoupling effects associated with heavy particles in the renormalization group running of the vacuum energy in a mass-dependent renormalization scheme. We find the running of the vacuum energy stemming from the Higgs condensate in the entire energy range and show that it behaves as expected from the simple dimensional arguments, meaning that it exhibits the quadratic sensitivity to the mass of the heavy particles in the infrared regime. The consequence of such a running to the fine-tuning problem with the measured value of the Cosmological Constant is analyzed and the constraint on the mass spectrum of a given model is derived. We show that in the Standard Model (SM) this fine-tuning constraint is not satisfied while in the massless theories this constraint formally coincides with the well-known Veltman condition. We also provide a remarkably simple extension of the SM where saturation of this constraint enables us to predict the radiative Higgs mass correctly. Generalization to constant curvature spaces is also given.

scholarly journals THE UNIT OF ELECTRIC CHARGE AND THE MASS HIERARCHY OF HEAVY PARTICLES

2007 ◽  
Vol 22 (38) ◽  
pp. 2909-2916
Author(s):  
G. LÓPEZ CASTRO ◽  
J. PESTIEAU
Keyword(s):  
Standard Model ◽  
Mass Hierarchy ◽  
Empirical Formulas ◽  
Heavy Particles ◽  
The Standard Model ◽  
Experimental Values ◽  
The One ◽  
Simple Ratio ◽  
The Masses ◽  
Good Agreement

We propose some empirical formulas relating the masses of the heaviest particles in the standard model (the W, Z, H bosons and the t quark) to the charge of the positron e and the Higgs condensate v. The relations for the masses of gauge bosons mW = (1+e)v/4 and [Formula: see text] are in good agreement with experimental values. By requiring the electroweak standard model to be free from quadratic divergences at the one-loop level, we find: [Formula: see text] and [Formula: see text], or the very simple ratio (mt/mH)2 = e.

DIRAC'S COSMOLOGY AND RADIOACTIVE DATING

1963 ◽  
Vol 41 (11) ◽  
pp. 1911-1923 ◽  
Author(s):  
E. R. Kanasewich ◽  
J. C. Savage
Keyword(s):  
Decay Rate ◽  
Decay Constant ◽  
The Other ◽  
Large Uncertainty ◽  
Β Decay ◽  
Α Decay ◽  
Age Of The Universe ◽  
The One ◽  
The Universe

It has long been recognized that Dirac's principle might imply that the rate of β decay would vary with the age of the universe. If so, the radioactive ages of meteorites and terrestrial rocks as indicated on the one hand by α decay and on the other by β decay should differ. However, the comparison of these ages is complicated by a large uncertainty in the decay constant for Rb87. Thus the age data must be analyzed to determine the decay constant most compatible with the particular theory of β decay which is used. Using this best decay constant for each theory, we find that the data are more consistent with a β decay rate independent of the age of the universe than with the dependence implied by the Dirac principle.

Qurʾānic Interpretative Latitude and Human Evolution: A Case Study

2014 ◽  
Vol 12 (2) ◽  
pp. 95-114
Author(s):  
DS Adnan Majid
Keyword(s):  
Human Evolution ◽  
Scientific Theory ◽  
Modern Science ◽  
The Other ◽  
Religion And Science ◽  
Age Of The Universe ◽  
The One ◽  
The Universe

Muslims today employ various and often conflicting strategies to mitigate contradictions between traditional Islamic teachings and modern science, especially in matters related to the age of the universe and the origin of humans. On the one hand, any scientific theory deemed problematic might be rejected outright; on the other, Islamic texts may be reinterpreted to fully support a novel scientific theory. There is, however, an alternative hermeneutical approach that uses intra-textual analysis to acknowledge “interpretative latitude” in the Qurʾān and other Islamic texts – the possibility that these texts allow for ambiguity and multiple interpretations that may or may not agree with modern science. In this paper, human evolution will serve as a case study of the implementation of this approach via a structured discussion of common Muslim objections to the theory. The paper will conclude with a discussion of the implications of this approach on defining the role of the Qurʾān and on the boundaries of religion and science.

scholarly journals Cosmological consequences of a variable cosmological constant model

2016 ◽  
Vol 26 (07) ◽  
pp. 1750060 ◽  
Author(s):  
Hemza Azri ◽  
A. Bounames
Keyword(s):  
Cosmological Constant ◽  
Vacuum Energy ◽  
Gravitational Constant ◽  
Scale Factor ◽  
Accelerated Expansion ◽  
Variable Cosmological Constant ◽  
Age Of The Universe ◽  
Two Phases ◽  
Limiting Case ◽  
The Universe

We derive a model of dark energy which evolves with time via the scale factor. The equation-of-state is studied as a function of a parameter [Formula: see text] introduced in this model as [Formula: see text]. In addition to the recent accelerated expansion, the model predicts another decelerated phase. These two phases are studied via the parameter [Formula: see text]. The age of the universe is found to be almost consistent with the observation. In the limiting case, the cosmological constant model, we find that vacuum energy gravitates with a tiny gravitational constant which evolves with the scale factor, rather than with Newton’s constant. This enables degravitation of the vacuum energy which in turn produces the tiny observed curvature, rather than a 120 orders of magnitude larger value.

scholarly journals CONNECTING THE NONSINGULAR ORIGIN OF THE UNIVERSE, THE VACUUM STRUCTURE AND THE COSMOLOGICAL CONSTANT PROBLEM

2013 ◽  
Vol 22 (09) ◽  
pp. 1330018 ◽  
Author(s):  
EDUARDO I. GUENDELMAN ◽  
PEDRO LABRAÑA
Keyword(s):  
Energy Density ◽  
Scale Invariance ◽  
Vacuum Energy ◽  
Vacuum Energy Density ◽  
Emergent Universe ◽  
Vacuum Structure ◽  
Inflationary Phase ◽  
Present Universe ◽  
The Universe ◽  
Origin Of The Universe

We consider a nonsingular origin for the universe starting from an Einstein static universe, the so-called "emergent universe" scenario, in the framework of a theory which uses two volume elements [Formula: see text] and Φd4x, where Φ is a metric independent density, used as an additional measure of integration. Also curvature, curvature square terms and for scale invariance a dilaton field ϕ are considered in the action. The first-order formalism is applied. The integration of the equations of motion associated with the new measure gives rise to the spontaneous symmetry breaking (SSB) of scale invariance (SI). After SSB of SI, it is found that a nontrivial potential for the dilaton is generated. In the Einstein frame we also add a cosmological term that parametrizes the zero point fluctuations. The resulting effective potential for the dilaton contains two flat regions, for ϕ → ∞ relevant for the nonsingular origin of the universe, followed by an inflationary phase and ϕ → -∞, describing our present universe. The dynamics of the scalar field becomes nonlinear and these nonlinearities produce a nontrivial vacuum structure for the theory and are responsible for the stability of some of the emergent universe solutions, which exists for a parameter range of values of the vacuum energy in ϕ → -∞, which must be positive but not very big, avoiding the extreme fine tuning required to keep the vacuum energy density of the present universe small. The nontrivial vacuum structure is crucial to ensure the smooth transition from the emerging phase, to an inflationary phase and finally to the slowly accelerated universe now. Zero vacuum energy density for the present universe defines the threshold for the creation of the universe.

scholarly journals Lyra’s cosmology of homogeneous and isotropic universe in Brans–Dicke theory

2020 ◽  
pp. 2150029
Author(s):  
Rajendra Prasad ◽  
Lalit Kumar Gupta ◽  
Anil Kumar Yadav
Keyword(s):  
Cosmological Model ◽  
Deceleration Parameter ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Density Parameter ◽  
Field Equations ◽  
Present Universe ◽  
Age Of The Universe ◽  
Geometrical Term ◽  
The Universe ◽  
Matter Energy

In this paper, we investigate a scalar field Brans–Dicke cosmological model in Lyra’s geometry which is based on the modifications in a geometrical term as well as energy term of Einstein’s field equations. We have examined the validity of the proposed cosmological model on the observational scale by performing statistical analysis from the latest [Formula: see text] and SN Ia observational data. We find that the estimated values of Hubble’s constant and matter energy density parameter is in agreement with their corresponding values, obtained from recent observations of Wilkinson Microwave Anisotropy Probe (WMAP) and Plank collaboration. We also derived the deceleration parameter, age of the universe and jerk parameter in terms of red-shift and computed its present values. The dynamics of the deceleration parameter in the derived model of the universe show a signature flipping from positive to a negative value and also indicate that the present universe is in the accelerating phase.

Review on Higgs Hidden-Dark Sector Physics

2021 ◽  
Author(s):  
Theodota Lagouri
Keyword(s):  
Standard Model ◽  
Weak Interactions ◽  
Hadron Collider ◽  
High Energy ◽  
Beyond The Standard Model ◽  
Future Prospects ◽  
Dark Sector ◽  
Hidden Sector ◽  
The Standard Model ◽  
The Universe

Abstract The Standard Model (SM), while extremely powerful as a description of the strong, electromagnetic and weak interactions, does not provide a natural candidate to explain Dark Matter (DM). Theoretical as well as experimental motivation exists for the existence of a hidden or dark sector of phenomena that couples either weakly or in a special way to SM fields. Hidden sector or dark sector states appear in many extensions to SM to provide a particular candidate DM in the universe or to explain astrophysical observations. If there is such a family of Beyond the Standard Model (BSM) particles and interactions, they may be accessible experimentally at the Large Hadron Collider (LHC) at CERN and at future High Energy Colliders. In this paper, the main focus is given on selected searches conducted at LHC experiments related to Higgs Hidden-Dark Sector Physics. The current constraints and future prospects of these studies are summarized.

scholarly journals The H0 Key Project: Cepheids in NGC925, M101 and M100

1995 ◽  
Vol 155 ◽  
pp. 258-259
Author(s):  
S. M. G. Hughes
Keyword(s):  
Standard Model ◽  
Hubble Space Telescope ◽  
Big Bang ◽  
Distance Scale ◽  
Space Telescope ◽  
The Standard Model ◽  
Age Of The Universe ◽  
Extragalactic Distance Scale ◽  
The Big Bang ◽  
The Universe

AbstractAs part of the Extragalactic Distance Scale Key Project, the Hubble Space Telescope has been used to identify Cepheids in M100, M101 and NGC925, and to measure distances derived from the Cepheid PL relation. For M100, the distance of 17.1 ± 1.8 Mpc has been used to infer a preliminary value for H0 of ~ 80 km/s/Mpc, which brings the age of the Universe derived from the standard model of the Big Bang into conflict with the ages of the oldest stars.

scholarly journals NONSINGULAR ORIGIN OF THE UNIVERSE AND THE COSMOLOGICAL CONSTANT PROBLEM

2011 ◽  
Vol 20 (14) ◽  
pp. 2767-2771 ◽  
Author(s):  
E. I. GUENDELMAN
Keyword(s):  
Vacuum Energy ◽  
Zero Point ◽  
Vacuum Energy Density ◽  
Cosmological Constant Problem ◽  
Static Universe ◽  
First Order ◽  
Present Universe ◽  
Einstein Static Universe ◽  
The Universe ◽  
Origin Of The Universe

We consider a nonsingular origin for the universe starting from an Einstein static universe in the framework of a theory which uses two volume elements [Formula: see text] and Φd4x, where Φ is a metric independent density, also curvature, curvature square terms, first order formalism and for scale invariance a dilaton field ϕ are considered in the action. In the Einstein frame we also add a cosmological term that parametrizes the zero point fluctuations. The resulting effective potential for the dilaton contains two flat regions, for ϕ → ∞ relevant for the nonsingular origin of the universe and ϕ → -∞, describing our present universe. Surprisingly, avoidance of singularities and stability as ϕ → ∞ imply a positive but small vacuum energy as ϕ → -∞. Zero vacuum energy density for the present universe is the "threshold" for universe creation.

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