Cosmology in multiply warped braneworld scenario

2014 ◽  
Vol 29 (13) ◽  
pp. 1450069 ◽  
Author(s):  
Narayan Banerjee ◽  
Sayantani Lahiri ◽  
Soumitra SenGupta
Keyword(s):  
Cosmological Constant ◽  
Extra Dimensions ◽  
Fine Tuning ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Hubble Expansion ◽  
Cosmological Scenario ◽  
Higher Dimensional ◽  
Gauge Hierarchy ◽  
Bulk Cosmological Constant

Hubble expansion in warped braneworld model is addressed in the presence of more than one warped extra dimensions. Some distinct phenomenological signatures of such model has already been discussed in the context of collider-based experiments as well as to explain the fermion mass hierarchy in the Standard Model of elementary particles. In this paper, we explore some cosmological implications of such a model. It is shown that while the expansion depends on all the moduli, an exponential nature of the expansion of the scale factor emerges as a generic feature which is independent of the number of extra dimensions but depends only on the bulk cosmological constant and brane pressure. A generalized expression for the effective 3-brane cosmological constant in such model has been derived. This generalizes the well-known fine tuning/detuning between the bulk cosmological constant and brane tension to obtain the desired cosmological constant on the brane. The warped factor corresponding to the higher-dimensional cosmological scenario is determined and the issue of gauge hierarchy problem is discussed.

scholarly journals A bottom-up approach to fermion mass hierarchy: a case with vector-like fermions

2020 ◽  
Vol 2020 (4) ◽  
Author(s):  
Yoshiharu Kawamura
Keyword(s):  
Standard Model ◽  
Yukawa Coupling ◽  
High Energy ◽  
Fine Tuning ◽  
Fermion Mass ◽  
Extended Model ◽  
Mass Hierarchy ◽  
Bottom Up ◽  
Existence Proofs ◽  
The Standard Model

Abstract We propose a bottom-up approach in which a structure of high-energy physics is explored by accumulating existence proofs and/or no-go theorems in the standard model or its extension. As an illustration, we study fermion mass hierarchies based on an extension of the standard model with vector-like fermions. It is shown that the magnitude of elements of Yukawa coupling matrices can become $O(1)$ and a Yukawa coupling unification can be realized in a theory beyond the extended model, if vector-like fermions mix with three families. In this case, small Yukawa couplings in the standard model can be highly sensitive to a small variation of matrix elements, and it seems that the mass hierarchy occurs as a result of fine tuning.

WARPED COMPACTIFICATION ON SIGMA MODEL, SKYRMIONS IN SIX DIMENSIONS

2007 ◽  
Vol 22 (31) ◽  
pp. 5670-5684 ◽  
Author(s):  
Yuta Kodama ◽  
Kento Kokubu ◽  
Nobuyuki Sawado ◽  
Noriko Shiiki
Keyword(s):  
Field Theory ◽  
Cosmological Constant ◽  
Effective Field Theory ◽  
Extra Dimensions ◽  
Sigma Model ◽  
Effective Field ◽  
Winding Number ◽  
Bulk Cosmological Constant ◽  
Six Dimensions

We construct two distinct brane solutions in six dimensional effective field theory models. The CP 1 sigma model and the baby skyrmion realize warped compactification of the extra dimensions for negative bulk cosmological constant. Higher winding number solutions of the baby skyrmion are also presented.

scholarly journals ON FERMION MASS HIERARCHY WITH EXTRA DIMENSIONS

2000 ◽  
Vol 15 (01) ◽  
pp. 29-39 ◽  
Author(s):  
KOICHI YOSHIOKA
Keyword(s):  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Atmospheric Neutrino ◽  
Fermion Mass ◽  
Neutrino Masses ◽  
Mass Hierarchy ◽  
Mixing Angles ◽  
Four Dimensions ◽  
Matter Fields ◽  
Neutrino Masses And Mixings

Recently, various phenomenological implications of the existence of extra space–time dimensions have been investigated. In this letter, we construct a model with realistic fermion mass hierarchy with (large) extra dimensions beyond the usual four dimensions. In this model, it is assumed that some matter fields live in the bulk and the others are confined to our four-dimensional wall. It can naturally reproduce the quark and lepton mass hierarchy and mixing angles without any symmetry arguments. We also discuss some possibilities of obtaining suitable neutrino masses and mixings for the solar and atmospheric neutrino problems.

scholarly journals Hyperbolic deformation of a gauge field theory and the hierarchy problem

2016 ◽  
Vol 31 (34) ◽  
pp. 1650177 ◽  
Author(s):  
R. Cartas-Fuentevilla ◽  
A. Escalante-Hernandez ◽  
A. Herrera-Aguilar
Keyword(s):  
Field Theory ◽  
Electromagnetic Coupling ◽  
Coupling Constants ◽  
Fine Tuning ◽  
Mass Hierarchy ◽  
Symmetry Breakdown ◽  
Hybrid Parts ◽  
Gauge Hierarchy ◽  
Mass Terms ◽  
Group Flow

The problem of the gauge hierarchy is brought up in a hypercomplex scheme for a [Formula: see text] field theory; in such a scheme, a compact gauge group is deformed through a [Formula: see text]-parameter that varies along a noncompact internal direction, transverse to the [Formula: see text] compact one, and thus an additional [Formula: see text] gauge symmetry is incorporated. This transverse direction can be understood as an extra internal dimension, which will control the spontaneous symmetry breakdown, and will allow us to establish a mass hierarchy. In this mechanism, there is no brane separation to be estabilized as in the braneworld paradigm, however, a different kind of fine-tuning is needed in order to generate the wished electroweak/Planck hierarchy. By analyzing the effective self-interactions and mass terms of the theory, an interesting duality is revealed between the real and hybrid parts of the effective potential. This duality relates the weak and strong self-interaction regimes of the theory, due to the fact that both mass terms and self-coupling constants appear as one-parameter flows in [Formula: see text]. Additionally, the [Formula: see text]-deformation will establish a flow for the electromagnetic coupling that mimics the renormalization group flow for the charge in QED.

Cosmological Constant Decaying with CMB Temperature

2018 ◽  
Author(s):  
Tomohide Sonoda
Keyword(s):  
Cosmological Constant ◽  
Fine Tuning ◽  
Theoretical Modelling ◽  
Microwave Background ◽  
Dark Energy Density ◽  
Large Numbers ◽  
Cosmological Scenario ◽  
The Hierarchical Structure ◽  
The Universe ◽  
Cmb Temperature

Recent observations of the dark energy density demonstrates the fine-tuning problem and challenges in theoretical modelling. In this study, we apply the self-similar symmetry (SSS) model, describing the hierarchical structure of the universe based on the Dirac large numbers hypothesis, to Einstein's cosmological term. We introduce a new similarity dimension, DB, in the SSS model. Using the DB SSS model, the cosmological constant Λ is simply expressed as a function of the cosmic microwave background (CMB) temperature. The result gives a natural interpretation of the cosmological scenario and helps understanding the extreme smallness of the present value of Λ without fine-tuning.

scholarly journals Supersymmetric large extra dimensions and the cosmological constant problem

2006 ◽  
Vol 84 (6-7) ◽  
pp. 463-472 ◽  
Author(s):  
C P Burgess
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Cosmological Constant ◽  
Present Status ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Cosmological Constant Problem ◽  
Dark Energy Density ◽  
Higher Dimensional

This article briefly summarizes and reviews the motivations for — and the present status of — the proposal that the small size of the observed Dark Energy density can be understood in terms of the dynamical relaxation of two large extra dimensions within a supersymmetric higher dimensional theory.PACS Nos.: 31.15.Pf, 31.30.Jv, 32.10.Hq

scholarly journals Phenomenology of a Supersymmetric Model for Fermion Mass Hierarchy

1997 ◽  
Vol 12 (05) ◽  
pp. 329-335 ◽  
Author(s):  
Chun Liu
Keyword(s):  
Electron Neutrino ◽  
Fine Tuning ◽  
Fermion Mass ◽  
Supersymmetric Model ◽  
Mass Hierarchy ◽  
Decay Modes ◽  
Lepton Number Violation ◽  
Lepton Universality ◽  
Experimental Bound ◽  
Near Future

Some phenomenological aspects of a supersymmetric model for fermion mass hierarchy proposed previously are discussed. It is required that the lepton universality violation is near to its current experimental bound. The lepton number violation decay modes τ→2eμ and 3μ maybe observable in the near future. The Majorana mass of electron-neutrino is predicted to be about 0.1 eV. The fine-tuning problem is discussed.

scholarly journals Constraining the Swiss-Cheese IR-Fixed Point Cosmology with Cosmic Expansion

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 263
Author(s):  
Ayan Mitra ◽  
Vasilios Zarikas ◽  
Alfio Bonanno ◽  
Michael Good ◽  
Ertan Güdekli
Keyword(s):  
Fixed Point ◽  
Cosmological Constant ◽  
Cosmic Acceleration ◽  
Fine Tuning ◽  
Clusters Of Galaxies ◽  
Swiss Cheese ◽  
Coincidence Problem ◽  
Cosmological Expansion ◽  
Cosmic Evolution ◽  
Previous Assumption

A recent work proposed that the recent cosmic passage to a cosmic acceleration era is the result of the existence of small anti-gravity sources in each galaxy and clusters of galaxies. In particular, a Swiss-cheese cosmology model, which relativistically integrates the contribution of all these anti-gravity sources on a galactic scale has been constructed assuming the presence of an infrared fixed point for a scale dependent cosmological constant. The derived cosmological expansion provides an explanation for both the fine tuning and the coincidence problem. The present work relaxes the previous assumption on the running of the cosmological constant and allows for a generic scaling around the infrared fixed point. Our analysis reveals that, in order to produce a cosmic evolution consistent with the best ΛCDM model, the IR-running of the cosmological constant is consistent with the presence of an IR-fixed point.

scholarly journals Unitarity in KK-graviton production, a case study in warped extra-dimensions

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
A. de Giorgi ◽  
S. Vogl
Keyword(s):  
Extra Dimensions ◽  
Sum Rules ◽  
Effective Theory ◽  
Higher Dimensional ◽  
Massive Spin ◽  
The Matrix ◽  
Dimensional Gravity ◽  
Warped Extra Dimensions ◽  
Kaluza Klein

Abstract The Kaluza-Klein (KK) decomposition of higher-dimensional gravity gives rise to a tower of KK-gravitons in the effective four-dimensional (4D) theory. Such massive spin-2 fields are known to be connected with unitarity issues and easily lead to a breakdown of the effective theory well below the naive scale of the interaction. However, the breakdown of the effective 4D theory is expected to be controlled by the parameters of the 5D theory. Working in a simplified Randall-Sundrum model we study the matrix elements for matter annihilations into massive gravitons. We find that truncating the KK-tower leads to an early breakdown of perturbative unitarity. However, by considering the full tower we obtain a set of sum rules for the couplings between the different KK-fields that restore unitarity up to the scale of the 5D theory. We prove analytically that these are fulfilled in the model under consideration and present numerical tests of their convergence. This work complements earlier studies that focused on graviton self-interactions and yields additional sum rules that are required if matter fields are incorporated into warped extra-dimensions.

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