Mass Hierarchy and Flat Directions in String Models

Cleaver, Gerald

doi:10.1007/0-306-47085-3_13

Cited by 5 publications

(18 citation statements)

References 15 publications

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“…A basis set of (norm-squares of) VEVs of scalar fields satisfying the non-anomalous D-flatness constraints (1.4) can be created en masse [15,16,17]. The basis directions can have positive, negative, or zero anomalous charge.…”

Section: Flat Directionsmentioning

confidence: 99%

“…The basis directions can have positive, negative, or zero anomalous charge. In the maximally orthogonal basis used in the singular value decomposition approach of [16,17], each basis direction is uniquely identified with a particular VEV. That is, although each basis direction generally contains many VEVs, each basis direction contains at least one particular VEV that only appears in it.…”

Section: Flat Directionsmentioning

confidence: 99%

“…Much of the study of the superstring models phenomenology (as well as nonstring supersymmetric models [14]) involves the analysis and classification of these flat directions. The methods for this analysis in string models have been systematised in [15,16,5,17].…”

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confidence: 99%

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Quasirealistic heterotic-string models with vanishing one-loop cosmological constant and perturbatively broken supersymmetry?

et al. 2008

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Quasi-realistic string models in the free fermionic formulation typically contain an anomalous U (1), which gives rise to a Fayet-Iliopoulos D-term that breaks supersymmetry at the one-loop level in string perturbation theory. Supersymmetry is traditionally restored by imposing F -and D-flatness on the vacuum. By employing the standard analysis of flat directions we present a quasi-realistic three generation string model in which stringent F -and Dflat solution do not appear to exist to all orders in the superpotential. We speculate that this result is indicative of the non-existence of supersymmetric flat F-and D-solutions in this model. We provide some arguments in support of this scenario and discuss its potential implications. Bose-Fermi degeneracy of the string spectrum implies that the one-loop partition function and hence the one-loop cosmological constant vanishes in the model. If our assertion is correct, this model may represent the first known example with vanishing cosmological constant and perturbatively broken supersymmetry. We discuss the distinctive properties of the internal free fermion boundary conditions that may correspond to a large set of models that share these properties. The geometrical moduli in this class of models are fixed due to asymmetric boundary conditions, whereas absence of supersymmetric flat directions would imply that the supersymmetric moduli are fixed as well and the dilaton may be fixed by hidden sector nonperturbative effects. *

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Section: Flat Directionsmentioning

confidence: 99%

Section: Flat Directionsmentioning

confidence: 99%

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Quasirealistic heterotic-string models with vanishing one-loop cosmological constant and perturbatively broken supersymmetry?

et al. 2008

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“…A basis can always be formed in which each element 16) where 17) where γ k is the overall scale factor and b ′ k,x are the relative ratios of the VEVs. Further, the scale factor of a basis element can always be normalized to 1, thereby leaving B k to be defined solely by the b (3.18) Neither the coefficients b ′ k,x [36] of a basis element B k , nor the weights w j,k [30] need all be non-negative, so long as the total contribution of all basis elements to an individual norm of a VEV, a j,x ≡ k w j,k b ′ k,x , in a flat direction C j is nonnegative [30]. However, a basis vector B k that contains at least one negative coefficient b ′ k,x < 0 cannot be viewed as a physical one-dimensional D-flat direction.…”

Section: D-flat Basis Setsmentioning

confidence: 99%

A Minimal Superstring Standard Model I: Flat Directions

Cleaver

Faraggi

Nanopoulos

2001

Int. J. Mod. Phys. A

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Three family SU (3) C × SU (2) L × U (1) Y string models in several constructions generically possess two features: (i) an extra local anomalous U (1) A and (ii) numerous (often fractionally charged) exotic particles beyond those in the minimal supersymmetric model (MSSM). Recently, we demonstrated that the observable sector effective field theory of such a free fermionic string model can reduce to that of the MSSM, with the standard observable gauge group being just SU (3) C × SU (2) L × U (1) Y and the SU (3) C × SU (2) L × U (1) Y -charged spectrum of the observable sector consisting solely of the MSSM spectrum. An example of a model with this property was shown. We continue our investigation of this model by presenting a large set of different flat directions of the same model that all produce the MSSM spectrum. Our results suggest that even after imposing the conditions for the decoupling of exotic states, there may remain sufficient freedom to satisfy the remaining phenomenological constraints imposed by the observed data.

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“…Thus, for the first time such a phenomenological analysis is carried out in a Minimal Superstring Standard Model. Second, and more importantly, in the phenomenological analysis performed in this paper, we implement the systematic techniques for the analysis of F and D flat directions that were developed over the last few years [5,6,7,2]. Relative to the more primitive studies performed in the past, our study here has the advantage that it incorporates in much of the analysis the non-renormalizable terms to all finite orders.…”

Section: Minimal Superstring Standard Modelsmentioning

confidence: 99%

Phenomenological study of a minimal superstring standard model

et al. 2001

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Recently, we demonstrated the existence of heterotic-string solutions in which the observable sector effective field theory just below the string scale reduces to that of the MSSM, with the standard observable gauge group being justspectrum of the observable sector consisting solely of the MSSM spectrum. Associated with this model is a set of distinct flat directions of vacuum expectation values (VEVs) of non-Abelian singlet fields that all produce solely the MSSM spectrum. In this paper, we study the effective superpotential induced by these choices of flat directions. We investigate whether sufficient degrees of freedom exist in these singlet flat directions to satisfy various phenomenological constraints imposed by the observed Standard Model data. For each flat direction, the effective superpotential is given to sixth order. The variations in the singlet and hidden sector low energy spectrums are analyzed. We then determine the mass matrices (to all finite orders) for the three generations of MSSM quarks and leptons. Possible Higgs µ-terms are investigated. We conclude by considering generalizations of our flat directions involving VEVs of non-Abelian fields. *

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Mass Hierarchy and Flat Directions in String Models

Cited by 5 publications

References 15 publications

Quasirealistic heterotic-string models with vanishing one-loop cosmological constant and perturbatively broken supersymmetry?

Quasirealistic heterotic-string models with vanishing one-loop cosmological constant and perturbatively broken supersymmetry?

A Minimal Superstring Standard Model I: Flat Directions

Phenomenological study of a minimal superstring standard model

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