scholarly journals Hierarchy problem and fine-tuning in a decoupling approach to multiscale effective potentials

2021 ◽  
Vol 104 (3) ◽  
Author(s):  
S. Biondini ◽  
D. Boer ◽  
R. Peeters
Keyword(s):  
Fine Tuning ◽  
Hierarchy Problem ◽  
Effective Potentials ◽  
Decoupling Approach

scholarly journals NONUNIVERSAL GAUGINO MASSES AND NATURAL SUPERSYMMETRY

2013 ◽  
Vol 28 (13) ◽  
pp. 1350046 ◽  
Author(s):  
ILIA GOGOLADZE ◽  
FARIHA NASIR ◽  
QAISAR SHAFI
Keyword(s):  
Standard Model ◽  
Quark Mass ◽  
Higgs Mass ◽  
Mass Range ◽  
Fine Tuning ◽  
Hierarchy Problem ◽  
Light Stop ◽  
High Scale ◽  
Little Hierarchy Problem ◽  
Gaugino Masses

We demonstrate that natural supersymmetry is readily realized in the framework of SU(4)c×SU(2)L×SU(2)Rwith nonuniversal gaugino masses. Focusing on ameliorating the little hierarchy problem, we explore the parameter space of this model which yields small fine-tuning measuring parameters (natural supersymmetry) at the electroweak scale (ΔEW) as well as at high scale (ΔHS). It is possible to have both ΔEWand ΔHSless than 100 in these models, (2% or better fine-tuning), while keeping the light CP-even (Standard Model-like) Higgs mass in the 123–127 GeV range. The light stop quark mass lies in the range [Formula: see text], and the range for the light stau lepton mass is [Formula: see text]. The first two family squarks are in the mass range [Formula: see text], and for the gluino we find [Formula: see text]. We do not find any solution with natural supersymmetry which yields significant enhancement for Higgs production and decay in the diphoton channel.

scholarly journals TwInflation

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Kaustubh Deshpande ◽  
Soubhik Kumar ◽  
Raman Sundrum
Keyword(s):  
General Structure ◽  
Ultra Violet ◽  
Effective Field ◽  
Fine Tuning ◽  
Hierarchy Problem ◽  
Future Directions ◽  
Cosmic Inflation ◽  
Hybrid Mechanism ◽  
The Face ◽  
Hybrid Inflation

Abstract The general structure of Hybrid Inflation remains a very well-motivated mechanism for lower-scale cosmic inflation in the face of improving constraints on the tensor-to-scalar ratio. However, as originally modeled, the “waterfall” field in this mechanism gives rise to a hierarchy problem (η−problem) for the inflaton after demanding standard effective field theory (EFT) control. We modify the hybrid mechanism and incorporate a discrete “twin” symmetry, thereby yielding a viable, natural and EFT-controlled model of non-supersymmetric low-scale inflation, “Twinflation”. Analogously to Twin Higgs models, the discrete exchange-symmetry with a “twin” sector reduces quadratic sensitivity in the inflationary potential to ultra-violet physics, at the root of the hierarchy problem. The observed phase of inflation takes place on a hilltop-like potential but without fine-tuning of the initial inflaton position in field-space. We also show that all parameters of the model can take natural values, below any associated EFT-cutoff mass scales and field values, thus ensuring straightforward theoretical control. We discuss the basic phenomenological considerations and constraints, as well as possible future directions.

scholarly journals Cosmology and Matter-Induced Branes

Symmetry ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 45 ◽  
Author(s):  
Sergey G. Rubin
Keyword(s):  
Significant Role ◽  
Cosmological Parameters ◽  
Fine Tuning ◽  
Matter Distribution ◽  
Hierarchy Problem ◽  
Planck Mass ◽  
Extra Space ◽  
Modern Physics ◽  
Cosmological Constants

The extra space paradigm plays a significant role in modern physics and cosmology as a specific case. In this review, the relation between the main cosmological parameters—the Planck mass and the Cosmological constants—and a metric of extra space is discussed. Matter distribution inside extra space and its effect on the 4-dimensional observational parameters is of particular interest. The ways to solve the fine-tuning problem and the hierarchy problem are analyzed.

NEUTRINO SPECTRUM IN NONSUPERSYMMETRIC SO(10)

1996 ◽  
Vol 11 (36) ◽  
pp. 2837-2848
Author(s):  
GABRIELA BARENBOIM
Keyword(s):  
Higgs Sector ◽  
Fine Tuning ◽  
Hierarchy Problem ◽  
Yukawa Couplings ◽  
Neutrino Spectrum ◽  
Fermion Masses ◽  
Mass Matrices

We present a predictive scheme for fermion masses and mixings inspired by nonsupersymmetric SO(10) in which the hierarchy problem is resolved without fine tuning the Yukawa couplings. This calls for a nonminimal Higgs sector which we exploit in deriving the expressions for the mass matrices. To keep the predictivity of the model under control we limit the structure of the mass matrices by imposing U(1) symmetries. A very predictive neutrino spectrum is then obtained.

LEE-WICK FIELD AS A DARK ENERGY CANDIDATE

2011 ◽  
Vol 01 ◽  
pp. 252-256 ◽  
Author(s):  
SEOKCHEON LEE
Keyword(s):  
Dark Energy ◽  
Energy Equation ◽  
State Parameter ◽  
Fine Tuning ◽  
Late Time ◽  
Hierarchy Problem ◽  
Phantom Divide ◽  
Higher Derivative ◽  
Accelerating Expansion ◽  
The Standard Model

As a possible alternative solution for the hierarchy problem in the standard model, Lee-Wick theory where a field has higher derivative kinetic operators has been paid attentions recently. Also in modern cosmology, the observations suggest that the current universe is under accelerating expansion dominated by dark energy. Furthermore, they marginally prefer the dark energy equation of state parameter ω DE to cross the phantom divide -1 at present. Lee-Wick theory has the same structure as so-called quintom model except the form of potentials and the sign of the slope of the potentials. Thus, this model can produce the stable late time phantom-dominated solution and maybe able to explain the current cosmology. However, without fine tuning of its mass we may not be able to produce the viable values of observational quantities in this model.

scholarly journals Cosmological fine tuning, supersymmetry and the gauge hierarchy problem

1999 ◽  
Vol 452 (1-2) ◽  
pp. 28-38 ◽  
Author(s):  
Piotr H. Chankowski ◽  
John Ellis ◽  
Keith A. Olive ◽  
Stefan Pokorski
Keyword(s):  
Fine Tuning ◽  
Hierarchy Problem ◽  
Gauge Hierarchy

scholarly journals GRAVITY, COSMOLOGY AND PARTICLE PHYSICS WITHOUT THE COSMOLOGICAL CONSTANT PROBLEM

1998 ◽  
Vol 13 (19) ◽  
pp. 1583-1586 ◽  
Author(s):  
E. I. GUENDELMAN ◽  
A. B. KAGANOVICH
Keyword(s):  
Cosmological Constant ◽  
Particle Physics ◽  
Vacuum Energy ◽  
Vacuum State ◽  
Scalar Fields ◽  
Fine Tuning ◽  
Gauge Fields ◽  
Hierarchy Problem ◽  
Cosmological Constant Problem ◽  
First Order

This letter elucidates recent achievements of the "nongravitating vacuum energy (NGVE) theory" which has the feature that a shift of the Lagrangian density by a constant does not affect dynamics. In the first-order formalism, a constraint appears that enforces the vanishing of the cosmological constant Λ. Standard dynamics of gauge unified theories (including fermions) and their SSB appear if a four-index field strength condensate is present. At the vacuum state, there is exact balance (to zero) of the gauge fields condensate and the original scalar fields potential. As a result it is possible to combine the solution of the Λ problem with inflation and transition to a Λ=0 phase without fine tuning after a reheating period. The model opens new possibilities for a solution of the hierarchy problem.

scholarly journals A REVIEW OF THREE-FAMILY GRAND UNIFIED STRING MODELS

1998 ◽  
Vol 13 (15) ◽  
pp. 2551-2598 ◽  
Author(s):  
ZURAB KAKUSHADZE ◽  
GARY SHIU ◽  
S.-H. HENRY TYE ◽  
YAN VTOROV-KAREVSKY
Keyword(s):  
Supersymmetry Breaking ◽  
Fine Tuning ◽  
Tree Level ◽  
Hierarchy Problem ◽  
Triplet Splitting ◽  
Mass Matrices ◽  
String Models ◽  
Proton Stability ◽  
Breaking Scale

We review the construction and classification of three-family grand unified models within the framework of asymmetric orbifolds in perturbative heterotic superstring. We give a detailed survey of all such models which is organized to aid analysis of their phenomenological properties. We compute tree level superpotentials for these models. These superpotentials are used to analyze the issues of proton stability (doublet–triplet splitting and R-parity-violating terms) and Yukawa mass matrices. To have agreement with phenomenological data all these models seem to require a certain degree of fine-tuning. We also analyze the possible patterns of supersymmetry breaking in these models. We find that the supersymmetry breaking scale comes out either too high to explain the electroweak hierarchy problem, or below the electroweak scale unless some degree of fine-tuning is involved. Thus, none of the models at hand seem to be phenomenologically flawless.

Fine-Tuning Futures

ASHA Leader ◽  
2017 ◽  
Vol 22 (6) ◽  
Author(s):  
Christi Miller
Keyword(s):  
Fine Tuning
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