scholarly journals Standard model from a supergravity model with a naturally small cosmological constant

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Shing Yan Li ◽  
Yu-Cheng Qiu ◽  
S.-H. Henry Tye
Keyword(s):  
String Theory ◽  
Standard Model ◽  
Cosmological Constant ◽  
Supersymmetry Breaking ◽  
Supersymmetric Standard Model ◽  
Degrees Of Freedom ◽  
Interaction Terms ◽  
Supersymmetric Version ◽  
The Standard Model ◽  
Linear Version

Abstract Guided by the naturalness criterion for an exponentially small cosmological constant, we present a string theory motivated 4-dimensional $$ \mathcal{N} $$ N = 1 non-linear supergravity model (or its linear version with a nilpotent superfield) with spontaneous supersymmetry breaking. The model encompasses the minimal supersymmetric standard model, the racetrack Kähler uplift, and the KKLT anti-D3-branes, and use the nilpotent superfield to project out the undesirable interaction terms as well as the unwanted degrees of freedom to end up with the standard model (not the supersymmetric version) of strong and electroweak interactions.

scholarly journals ON THE FORMULATION OF THE GENERIC SUPERSYMMETRIC STANDARD MODEL (OR SUPERSYMMETRY WITHOUT R PARITY)

2004 ◽  
Vol 19 (12) ◽  
pp. 1863-1892 ◽  
Author(s):  
OTTO C. W. KONG
Keyword(s):  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Ad Hoc ◽  
Discrete Symmetry ◽  
Tree Level ◽  
Gauge Symmetries ◽  
Supersymmetric Version ◽  
Mass Matrices ◽  
The Standard Model ◽  
Soft Supersymmetry Breaking

The generic supersymmetric version of the Standard Model would have the minimal list of superfields incorporating the Standard Model particles, and a Lagrangian dictated by the Standard Model gauge symmetries. To be phenomenologically viable, soft supersymmetry breaking terms have to be included. In the most popular version of the supersymmetric Standard Model, an ad hoc discrete symmetry, called R parity, is added in by hand. While there has been a lot of various kinds of R-parity violation studies in the literature, the complete version of supersymmetry without R parity is not popularly appreciated. In this article, we present a pedagogical review of the formulation of this generic supersymmetric Standard Model and give a detailed discussion on the basic conceptual issues involved. Unfortunately, there are quite some confusing, or even plainly wrong, statements on the issues within the literature of R-parity violations. We aim at clarifying these issues here. We will first discuss our formulation, about which readers are urged to read without bias from previous acquired perspectives on the topic. Based on the formulation, we will then address the various issues. In relation to phenomenology, our review here will not go beyond tree-level mass matrices. But we will give a careful discussion of mass matrices of all the matter fields involved. Useful expressions for perturbative diagonalizations of the mass matrices at the phenomenologically interesting limit of corresponds to small neutrino masses are derived. All these expressions are given in the fully generic setting, with information on complex phases of parameters retained. Such expressions have been shown to be useful in the analyses of various phenomenological features.

Perspective on the weakly coupled heterotic string

2015 ◽  
Vol 30 (08) ◽  
pp. 1530005 ◽  
Author(s):  
Mary K. Gaillard
Keyword(s):  
String Theory ◽  
Standard Model ◽  
Supersymmetry Breaking ◽  
Heterotic String ◽  
Particle Spectrum ◽  
Promising Candidate ◽  
Heterotic String Theory ◽  
Hidden Sector ◽  
Weakly Coupled ◽  
The Standard Model

Since the first "string revolution" of 1984, the weakly coupled E8⊗E8 heterotic string theory has been a promising candidate for the underlying theory of the Standard Model. The particle spectrum and the issue of dilaton stabilization are reviewed. Specific models for hidden sector condensation and supersymmetry breaking are described and their phenomenological and cosmological implications are discussed. The importance of T-duality is emphasized. Theoretical challenges to finding a satisfactory vacuum, as well as constraints from LHC data are addressed.

scholarly journals A minimal supersymmetric left-right model, dark matter and signals at the LHC

2020 ◽  
Vol 229 (21) ◽  
pp. 3187-3203
Author(s):  
Katri Huitu
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Dark Matter Particle ◽  
Supersymmetric Particle ◽  
Additional Symmetry ◽  
Supersymmetric Version ◽  
The Standard Model ◽  
Left And Right ◽  
The Universe

AbstractThe left-right symmetric models extend the gauge group of the Standard Model enabling treatment of the left- and right-handed fermions in the same footing. The left-right symmetry requires the existence of right-handed neutrinos, leading naturally to non-zero masses for neutrinos. Here some aspects of a supersymmetric version of the left-right symmetric models are reviewed. Such models have many virtues, including possibility for dark matter without any new additional symmetry needed in order to have a stable lightest supersymmetric particle. In the model the lightest sneutrino or the lightest neutralino can form dark matter of the universe, at the same time fulfilling all the experimental constraints. The dark matter particle in the model can be very different from the dark matter typical in the minimal supersymmetric standard model. Specific signals for this kind of models at the LHC are also discussed.

scholarly journals Linking the supersymmetric standard model to the cosmological constant

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Yu-Cheng Qiu ◽  
S.-H. Henry Tye
Keyword(s):  
String Theory ◽  
Standard Model ◽  
Cosmological Constant ◽  
Supersymmetric Standard Model ◽  
Local Minimum ◽  
Planck Scale ◽  
Susy Breaking ◽  
Higgs Fields ◽  
Breaking Scale ◽  
Exponentially Small

Abstract String theory has no parameter except the string scale MS, so the Planck scale MPl, the supersymmetry-breaking scale "Image missing", the electroweak scale mEW as well as the vacuum energy density (cosmological constant) Λ are to be determined dynamically at any local minimum solution in the string theory landscape. Here we consider a model that links the supersymmetric electroweak phenomenology (bottom up) to the string theory motivated flux compactification approach (top down). In this model, supersymmetry is broken by a combination of the racetrack Kähler uplift mechanism, which naturally allows an exponentially small positive Λ in a local minimum, and the anti-D3-brane in the KKLT scenario. In the absence of the Higgs doublets from the supersymmetric standard model, one has either a small Λ or a big enough "Image missing", but not both. The introduction of the Higgs fields (with their soft terms) allows a small Λ and a big enough "Image missing" simultaneously. Since an exponentially small Λ is statistically preferred (as the properly normalized probability distribution P(Λ) diverges at Λ = 0+), identifying the observed Λobs to the median value Λ50% yields mEW∼ 100 GeV. We also find that the warped anti-D3-brane tension has a SUSY-breaking scale "Image missing" ∼ 100 mEW while the SUSY-breaking scale that directly correlates with the Higgs fields in the visible sector is "Image missing" ≃ mEW.

scholarly journals Lorentz Violation of the Photon Sector in Field Theory Models

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Lingli Zhou ◽  
Bo-Qiang Ma
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Degrees Of Freedom ◽  
Lorentz Violation ◽  
Detailed Structure ◽  
Standard Model Extension ◽  
Model Extension ◽  
The Standard Model ◽  
Minimal Standard

We compare the Lorentz violation terms of the pure photon sector between two field theory models, namely, the minimal standard model extension (SME) and the standard model supplement (SMS). From the requirement of the identity of the intersection for the two models, we find that the free photon sector of the SMS can be a subset of the photon sector of the minimal SME. We not only obtain some relations between the SME parameters but also get some constraints on the SMS parameters from the SME parameters. The CPT-odd coefficients(kAF)αof the SME are predicted to be zero. There are 15 degrees of freedom in the Lorentz violation matrixΔαβof free photons of the SMS related with the same number of degrees of freedom in the tensor coefficients(kF)αβμν, which are independent from each other in the minimal SME but are interrelated in the intersection of the SMS and the minimal SME. With the related degrees of freedom, we obtain the conservative constraints(2σ)on the elements of the photon Lorentz violation matrix. The detailed structure of the photon Lorentz violation matrix suggests some applications to the Lorentz violation experiments for photons.

scholarly journals DARK MATTER, AND ITS DARKNESS

2006 ◽  
Vol 15 (12) ◽  
pp. 2267-2278 ◽  
Author(s):  
D. V. AHLUWALIA-KHALILOVA
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Cosmological Constant ◽  
Model Material ◽  
Representation Space ◽  
Spatial Curvature ◽  
The Standard Model ◽  
General Relativistic ◽  
Relativistic Description ◽  
Friedmann Robertson Walker

Assuming the validity of the general relativistic description of gravitation on astrophysical and cosmological length scales, we analytically infer that the Friedmann–Robertson–Walker cosmology with Einsteinian cosmological constant, and a vanishing spatial curvature constant, unambiguously requires a significant amount of dark matter. This requirement is consistent with other indications for dark matter. The same space–time symmetries that underlie the freely falling frames of Einsteinian gravity also provide symmetries which, for the spin one half representation space, furnish a novel construct that carries extremely limited interactions with respect to the terrestrial detectors made of the standard model material. Both the "luminous" and "dark" matter turn out to be residents of the same representation space but they derive their respective "luminosity" and "darkness" from either belonging to the sector with (CPT)2 = +𝟙, or to the sector with (CPT)2 = -𝟙.

SCALE GAUGE SYMMETRY AND THE STANDARD MODEL

1990 ◽  
Vol 05 (22) ◽  
pp. 4225-4240 ◽  
Author(s):  
J. SOLÀ
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Cosmological Constant ◽  
Minimal Model ◽  
Harmonic Map ◽  
Strong Interactions ◽  
Cosmological Constant Problem ◽  
The Standard Model ◽  
Conformal Gauge ◽  
Scalar Sector

We speculate on a version of the "standard" model of the electroweak and strong interactions coupled to gravity and equipped with a spontaneously broken, anomalous, conformal gauge symmetry. The scalar sector is virtually absent in the minimal model but in the general case it shows up in the form of a nonlinear harmonic map Lagrangian. A Euclidean approach to the cosmological constant problem is also addressed in this framework.

scholarly journals The force and gravity of events

2016 ◽  
Vol 31 (16) ◽  
pp. 1630015 ◽  
Author(s):  
Robert Delbourgo
Keyword(s):  
Standard Model ◽  
Cosmological Constant ◽  
Ricci Scalar ◽  
The Other ◽  
Gauge Fields ◽  
Generalized Metric ◽  
The Standard Model ◽  
Property Space

Local events are characterized by “where”, “when” and “what”. Just as (bosonic) spacetime forms the backdrop for location and time, (fermionic) property space can serve as the backdrop for the attributes of a system. With such a scenario I shall describe a scheme that is capable of unifying gravitation and the other forces of nature. The generalized metric contains the curvature of spacetime and property separately, with the gauge fields linking the bosonic and fermionic arenas. The super-Ricci scalar can then automatically yield the spacetime Lagrangian of gravitation and the Standard Model (plus a cosmological constant) upon integration over property coordinates.

scholarly journals HIGGS MASS FROM A CASIMIR ENERGY INDUCED COSMOLOGICAL CONSTANT IN THE STANDARD MODEL

2004 ◽  
Vol 19 (13n16) ◽  
pp. 1195-1201
Author(s):  
XIAO-GANG HE
Keyword(s):  
Standard Model ◽  
Symmetry Breaking ◽  
Cosmological Constant ◽  
Spontaneous Symmetry Breaking ◽  
Particle Physics ◽  
Higgs Mass ◽  
Vacuum Energy ◽  
Casimir Energy ◽  
Renormalization Scale ◽  
The Standard Model

Casimir vacuum energy is divergent. It needs to be regularized. The regularization introduces a renormalization scale which may lead to a scale dependent cosmological constant. We show that the requirement of physical cosmological constant is renormalization scale independent provides important constraints on possible particle contents and their masses in particle physics models. In the Standard Model of strong and electroweak interactions, besides the Casimir vacuum energy there is also vacuum energy induced from spontaneous symmetry breaking. The requirement that the total vacuum energy to be scale independent dictates the Higgs mass to be [Formula: see text] where the summation is over fermions and Ni equals to 3 and 1 for quarks and leptons, respectively. The Higgs mass is predicted to be approximately 382 GeV.

scholarly journals A simple assessment on the hierarchy problem

2016 ◽  
Vol 13 (06) ◽  
pp. 1650068 ◽  
Author(s):  
Luca Fabbri
Keyword(s):  
Standard Model ◽  
Cosmological Constant ◽  
Scalar Fields ◽  
Hierarchy Problem ◽  
Cosmological Constant Problem ◽  
The Standard Model

We consider the simplest extension of the standard model, where torsion couples to spinor as well as the scalar fields, and in which the cosmological constant problem is solved.

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