scholarly journals M-Theory Inspired No-Scale Supergravity

1997 ◽  
Vol 12 (35) ◽  
pp. 2647-2653 ◽  
Author(s):  
Tianjun Li ◽  
D. V. Nanopoulos ◽  
Jorge L. Lopez
Keyword(s):  
Supersymmetry Breaking ◽  
Gauge Coupling ◽  
Heterotic String ◽  
Particle Accelerators ◽  
Intermediate Scale ◽  
Strongly Coupled ◽  
Present Generation ◽  
Kähler Potential ◽  
M Theory

We propose a supergravity model that contains elements recently shown to arise in the strongly-coupled limit of the E8 × E8 heterotic string (M-theory), including a no-scale-like Kähler potential, the identification of the string scale with the gauge coupling unification scale, and the onset of supersymmetry breaking at an intermediate scale determined by the size of the 11th dimension of M-theory. We also study the phenomenological consequences of such scenario, which include a rather constrained sparticle spectrum within the reach of present-generation particle accelerators.

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 Primordial monopoles and strings, inflation, and gravity waves

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Joydeep Chakrabortty ◽  
George Lazarides ◽  
Rinku Maji ◽  
Qaisar Shafi
Keyword(s):  
Symmetry Breaking ◽  
Gravity Waves ◽  
Cosmic Strings ◽  
Wave Spectrum ◽  
Gauge Coupling ◽  
String Tension ◽  
Magnetic Monopoles ◽  
Intermediate Scale ◽  
Tension Parameter ◽  
The Universe

Abstract We consider magnetic monopoles and strings that appear in non-supersymmetric SO(10) and E6 grand unified models paying attention to gauge coupling unification and proton decay in a variety of symmetry breaking schemes. The dimensionless string tension parameter Gμ spans the range 10−6− 10−30, where G is Newton’s constant and μ is the string tension. We show how intermediate scale monopoles with mass ∼ 1013− 1014 GeV and flux ≲ 2.8 × 10−16 cm−2s−1sr−1, and cosmic strings with Gμ ∼ 10−11− 10−10 survive inflation and are present in the universe at an observable level. We estimate the gravity wave spectrum emitted from cosmic strings taking into account inflation driven by a Coleman-Weinberg potential. The tensor-to-scalar ratio r lies between 0.06 and 0.003 depending on the details of the inflationary scenario.

scholarly journals Observable proton decay in flipped SU(5)

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Maria Mehmood ◽  
Mansoor Ur Rehman ◽  
Qaisar Shafi
Keyword(s):  
Neutrino Mass ◽  
Gauge Coupling ◽  
Proton Decay ◽  
Type I ◽  
Mass Model ◽  
Intermediate Scale ◽  
Decay Channels ◽  
Proton Lifetime ◽  
Hybrid Inflation ◽  
Neutrino Mass Models

Abstract We explore proton decay in a class of realistic supersymmetric flipped SU(5) models supplemented by a U(1)R symmetry which plays an essential role in implementing hybrid inflation. Two distinct neutrino mass models, based on inverse seesaw and type I seesaw, are identified, with the latter arising from the breaking of U(1)R by nonrenormalizable superpotential terms. Depending on the neutrino mass model an appropriate set of intermediate scale color triplets from the Higgs superfields play a key role in proton decay channels that include p → (e+, μ+) π0, p → (e+, μ+) K0, p →$$ \overline{v}{\pi}^{+} $$ v ¯ π + , and p →$$ \overline{v}{K}^{+} $$ v ¯ K + . We identify regions of the parameter space that yield proton lifetime estimates which are testable at Hyper-Kamiokande and other next generation experiments. We discuss how gauge coupling unification in the presence of intermediate scale particles is realized, and a Z4 symmetry is utilized to show how such intermediate scales can arise in flipped SU(5). Finally, we compare our predictions for proton decay with previous work based on SU(5) and flipped SU(5).

scholarly journals Five-branes and supersymmetry breaking in M-Theory

1999 ◽  
Vol 1999 (04) ◽  
pp. 009-009 ◽  
Author(s):  
André Lukas ◽  
Burt A Ovrut ◽  
Daniel Waldram
Keyword(s):  
Supersymmetry Breaking ◽  
M Theory

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 Vacuum Constraints for Realistic Strongly Coupled Heterotic M-Theories

Symmetry ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 723
Author(s):  
Burt Ovrut
Keyword(s):  
Field Theory ◽  
Vector Bundle ◽  
Domain Wall ◽  
Effective Field Theory ◽  
Effective Field ◽  
Anomaly Cancellation ◽  
Strongly Coupled ◽  
Hidden Sector ◽  
M Theory ◽  
Bulk Space

The compactification from the 11-dimensional Horava-Witten orbifold to 5-dimensional heterotic M-theory on a Schoen Calabi-Yau threefold is reviewed, as is the specific S U ( 4 ) vector bundle leading to the “heterotic standard model” in the observable sector. A generic formalism for a consistent hidden sector gauge bundle, within the context of strongly coupled heterotic M-theory, is presented. Anomaly cancellation and the associated bulk space 5-branes are discussed in this context. The further compactification to a 4-dimensional effective field theory on a linearized BPS double domain wall is then presented to order κ 11 4 / 3 . Specifically, the generic constraints required for anomaly cancellation and by the linearized domain wall solution, restrictions imposed by the vanishing of the D-terms and, finally, the constraints imposed by the necessity for positive, perturbative squared gauge couplings to this order are presented in detail.

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