Scale hierarchies and string cosmology

2017 ◽  
Vol 32 (17) ◽  
pp. 1730012
Author(s):  
I. Antoniadis
Keyword(s):  
Cosmological Constant ◽  
Supersymmetry Breaking ◽  
Scalar Potential ◽  
String Cosmology ◽  
Low Energy ◽  
Chiral Multiplet ◽  
Positive Cosmological Constant ◽  
Shift Symmetry ◽  
Kähler Potential ◽  
Soft Supersymmetry Breaking

I describe the phenomenology of a model of supersymmetry breaking in the presence of a tiny (tuneable) positive cosmological constant. It utilizes a single chiral multiplet with a gauged shift symmetry, that can be identified with the string dilaton (or an appropriate compactification modulus). The model is coupled to the MSSM, leading to calculable soft supersymmetry breaking masses and a distinct low energy phenomenology that allows to differentiate it from other models of supersymmetry breaking and mediation mechanisms. We also study the question if this model can lead to inflation by identifying the dilaton with the inflaton. We find that this is possible if the Kähler potential is modified by a term that has the form of NS5-brane instantons, leading to an appropriate inflationary plateau around the maximum of the scalar potential, depending on two extra parameters.

scholarly journals Scale hierarchies in particle physics and cosmology

2018 ◽  
Vol 182 ◽  
pp. 02005
Author(s):  
I. Antoniadis
Keyword(s):  
Cosmological Constant ◽  
Supersymmetry Breaking ◽  
Particle Physics ◽  
Scalar Potential ◽  
Low Energy ◽  
Chiral Multiplet ◽  
Positive Cosmological Constant ◽  
Shift Symmetry ◽  
Kähler Potential ◽  
Soft Supersymmetry Breaking

I describe the phenomenology of a model of supersymmetry breaking in the presence of a tiny (tuneable) positive cosmological constant. It utilises a single chiral multiplet with a gauged shift symmetry, that can be identified with the string dilaton (or an appropriate compactification modulus). The model is coupled to the MSSM, leading to calculable soft supersymmetry breaking masses and a distinct low energy phenomenology that allows to differentiate it from other models of supersymmetry breaking and mediation mechanisms. We also study the question if this model can lead to inflation by identifying the dilaton with the inflaton. We find that this is possible if the Kähler potential is modified by a term that has the form of NS5-brane instantons, leading to an appropriate inflationary plateau around the maximum of the scalar potential, depending on two extra parameters.

scholarly journals Explicit soft supersymmetry breaking in the heterotic M-theory B − L MSSM

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Anthony Ashmore ◽  
Sebastian Dumitru ◽  
Burt A. Ovrut
Keyword(s):  
Line Bundle ◽  
Supersymmetry Breaking ◽  
Moduli Space ◽  
Initial Conditions ◽  
Low Energy ◽  
Strongly Coupled ◽  
Hidden Sector ◽  
Effective Lagrangian ◽  
Soft Supersymmetry Breaking ◽  
M Theory

Abstract The strongly coupled heterotic M-theory vacuum for both the observable and hidden sectors of the B − L MSSM theory is reviewed, including a discussion of the “bundle” constraints that both the observable sector SU(4) vector bundle and the hidden sector bundle induced from a single line bundle must satisfy. Gaugino condensation is then introduced within this context, and the hidden sector bundles that exhibit gaugino condensation are presented. The condensation scale is computed, singling out one line bundle whose associated condensation scale is low enough to be compatible with the energy scales available at the LHC. The corresponding region of Kähler moduli space where all bundle constraints are satisfied is presented. The generic form of the moduli dependent F-terms due to a gaugino superpotential — which spontaneously break N = 1 supersymmetry in this sector — is presented and then given explicitly for the unique line bundle associated with the low condensation scale. The moduli-dependent coefficients for each of the gaugino and scalar field soft supersymmetry breaking terms are computed leading to a low-energy effective Lagrangian for the observable sector matter fields. We then show that at a large number of points in Kähler moduli space that satisfy all “bundle” constraints, these coefficients are initial conditions for the renormalization group equations which, at low energy, lead to completely realistic physics satisfying all phenomenological constraints. Finally, we show that a substantial number of these initial points also satisfy a final constraint arising from the quadratic Higgs-Higgs conjugate soft supersymmetry breaking term.

scholarly journals THE GRACEFUL EXIT FROM THE ANOMALY-INDUCED INFLATION: SUPERSYMMETRY AS A KEY

2002 ◽  
Vol 11 (08) ◽  
pp. 1159-1169 ◽  
Author(s):  
I. L. SHAPIRO
Keyword(s):  
Supersymmetry Breaking ◽  
Low Energy ◽  
Fine Tuning ◽  
Starobinsky Model ◽  
Expansion Of The Universe ◽  
Soft Supersymmetry Breaking ◽  
The Universe

The stable version of the anomaly-induced inflation does not need a fine tuning to induce sufficient expansion of the Universe. The non-stable version (Starobinsky model) provides the graceful exit to the FRW phase. Here, we indicate the possibility of the inflation which is stable at the beginning and unstable at the end. The effect is due to the soft supersymmetry breaking and the decoupling of the massive sparticles at low energy.

scholarly journals Soft supersymmetry breaking with tiny cosmological constant in flux compactified N=1 supergravity

2011 ◽  
Vol 701 (3) ◽  
pp. 367-372 ◽  
Author(s):  
Debottam Das ◽  
Joydip Mitra ◽  
Sudipto Paul Chowdhury ◽  
Soumitra SenGupta
Keyword(s):  
Cosmological Constant ◽  
Supersymmetry Breaking ◽  
Soft Supersymmetry Breaking

Soft supersymmetry breaking in superstring-based low-energy supergravity

1988 ◽  
Vol 203 (4) ◽  
pp. 400-402 ◽  
Author(s):  
Parthasarathi Majumdar ◽  
Soumitra Sengupta
Keyword(s):  
Supersymmetry Breaking ◽  
Low Energy ◽  
Soft Supersymmetry Breaking

scholarly journals STRING NO-SCALE SUPERGRAVITY

1996 ◽  
Vol 11 (19) ◽  
pp. 3439-3477 ◽  
Author(s):  
JORGE L. LOPEZ ◽  
D.V. NANOPOULOS
Keyword(s):  
Supersymmetry Breaking ◽  
Vacuum Energy ◽  
Scalar Potential ◽  
Gauge Coupling ◽  
Supersymmetric Particle ◽  
Scale Models ◽  
Fermionic String ◽  
Soft Supersymmetry Breaking ◽  
The Stability ◽  
String Models

We explore the postulates of string no-scale supergravity in the context of free-fermionic string models. The requirements of vanishing vacuum energy, flat directions of the scalar potential, and stable no-scale mechanism impose strong restrictions on possible string no-scale models, which must possess only two or three moduli, and a constrained massless spectrum. The soft-supersymmetry-breaking parameters involving all twisted and untwisted fields are given explicitly. Our calculations take into account the possible existence of an anomalous U A(1) factor in the gauge group, and reveal some novel effects concerning the stability of the no-scale mechanism in the presence of U A(1). This class of models contains no free parameters, i.e. in principle all supersymmetric particle masses and interactions are completely determined. A computerized search for free-fermionic models with the desired properties yields a candidate SU (5)×U(1) model containing extra [Formula: see text] matter representations that allow gauge coupling unification at the string scale. Our candidate model possesses a benign nonuniversal assignment of supersymmetry-breaking scalar masses, which may have interesting low-energy experimental consequences.

scholarly journals MATTER-COUPLED SUPERGRAVITY WITH GAUSS-BONNET INVARIANTS: COMPONENT LAGRANGIAN AND SUPERSYMMETRY BREAKING

1988 ◽  
Vol 03 (07) ◽  
pp. 1675-1733 ◽  
Author(s):  
S. CECOTTI ◽  
S. FERRARA ◽  
L. GIRARDELLO ◽  
A. PASQUINUCCI ◽  
M. PORRATI
Keyword(s):  
Supersymmetry Breaking ◽  
Scalar Potential ◽  
Low Energy ◽  
Closed Form Expression ◽  
Physical Vacuum ◽  
Energy Limit ◽  
Form Expression ◽  
Four Dimensions ◽  
Heterotic Strings ◽  
Infinite Mass

We present the component Lagrangian for the general coupling of N=1 matter to a higher curvature four-dimensional supergravity in which the (curvature)2 terms enter the Lagrangian only through the Gauss-Bonnet and Hirzebruch invariants. This is the situation suggested by the low-energy limit of heterotic strings, after compactification to four dimensions. The model obtained from the string by SU(3)-invariant truncation of the toroidal compactification is discussed in detail. We give the closed-form expression for the scalar potential and discuss supersymmetry breaking via gaugino condensation. We show that, in this last case, the cosmological constant Λ remains exactly zero even when the higher curvature corrections are taken into account. We also discuss briefly the problem of auxiliary field propagation and show that the spurious states decouple (i.e. they get an infinite mass) on the physical vacuum with Λ=0, irrespective of whether SUSY is broken or not. Some new, stringy, developments are discussed in the last section.

STRINGY EFFECTS ON SUPERSYMMETRY BREAKING IN LOW ENERGY SUPERGRAVITY THEORIES

1991 ◽  
Vol 06 (01) ◽  
pp. 41-58
Author(s):  
SOUMITRA SENGUPTA ◽  
PARTHASARATHI MAJUMDAR
Keyword(s):  
Supersymmetry Breaking ◽  
Quantum Effects ◽  
Low Energy ◽  
Tree Level ◽  
World Sheet ◽  
Supergravity Theory ◽  
The World ◽  
String Loop ◽  
Mass Terms ◽  
Soft Supersymmetry Breaking

The possibility of soft supersymmetry breaking at the tree level of string-inspired low energy supergravity theory is investigated. It is shown that the stringy quantum effects like the world sheet instanton and string loop effects can induce soft supersymmetry breakings at the tree level of the observable sector. Generic mass terms and trilinear soft breaking terms that arise are calculated.

scholarly journals Further Studies of the Supersymmetric NJL-Type Model for a Real Superfield Composite

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1818
Author(s):  
Yifan Cheng ◽  
Yan-Min Dai ◽  
Gaber Faisel ◽  
Otto C. W. Kong
Keyword(s):  
Supersymmetry Breaking ◽  
Mass Term ◽  
Effective Theory ◽  
Type Model ◽  
Nontrivial Solutions ◽  
Vacuum Condensate ◽  
Kähler Potential ◽  
Soft Supersymmetry Breaking ◽  
Vacuum Solutions ◽  
Chiral Superfield

This is a sequel to our earlier paper presenting a supersymmetric Nambu–Jona–Lasinio (NJL)-type model for a real superfield composite. The model in the simplest version has only a chiral superfield (multiplet), with a strong four-superfield interaction in the Kähler potential that induces a real two-superfield composite with vacuum condensate. The latter can have supersymmetry breaking parts, which we have shown to bear nontrivial solutions under a standard nonperturbative analysis for a Nambu–Jona–Lasinio-type model on a superfield setting. In this article, we generalize our earlier analysis by allowing a supersymmetric mass term for the chiral superfield, as well as possible θ2 components for the soft supersymmetry breaking part of the condensate. We present admissible nontrivial vacuum solutions and an analysis of the resulted low energy effective theory with components of the composite becoming dynamical. The determinant of the fermionic modes is shown to be zero, illustrating the presence of the expected Goldstino.

scholarly journals INFLATION FROM SUPERSTRINGS

1996 ◽  
Vol 05 (05) ◽  
pp. 541-565
Author(s):  
A. DE LA MACORRA ◽  
S. LOLA
Keyword(s):  
Supersymmetry Breaking ◽  
Parameter Space ◽  
Density Fluctuations ◽  
Low Energy ◽  
Specific Scheme ◽  
Kähler Potential ◽  
Matter Fields

We investigate the possibility of obtaining inflationary solutions from a low energy Lagrangian coming from superstrings. In any viable scheme, the dilaton and the moduli fields have to be stabilized and before this happens, no other field may be used as the inflaton. We show that in a class of models where supersymmetry breaking occurs via gaugino condensation, the dilaton and the moduli fields can be stabilised in a way that enables the use of chiral matter fields in order to obtain enough e-folds of inflation. In a superstring model this is not straightforward, because the form of the Kähler potential is restricted and certain relations between the chiral and moduli fields lead in general to a steep potential. We identify a subclass of Kähler potentials and a certain region of the parameter space of the chiral and moduli fields that may lead to enough inflation. The conditions that we have derived for inflation due to chiral fields are generic and apply also in schemes where the dilaton and moduli fields may be frozen in alternative ways. Demanding that the potential terms associated with the chiral fields do not spoil the dilaton and moduli minimization under the specific scheme that we use to freeze the dilaton, leads to severe constraints on the magnitude of the density fluctuations.

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