Nonrenormalizable terms in the free fermionic formulation of 4D strings

Kalara, S.; López, Jorge L.; Nanopoulos, Dimitri V.

doi:10.1016/0370-2693(90)90668-v

Cited by 77 publications

(88 citation statements)

References 52 publications

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“…Further details on the derivation of these rules are given in ref. [5]. Renormalizable and nonrenormalizable contributions to the superpotential are obtained by calculating correlators between vertex operators…”

Section: Tools For Calculating the Fermion Mass Termsmentioning

confidence: 99%

“…An odd (even) order term requires an even (odd) number of picture changing operations to get the correct ghost number [5]. Thus, for A N to be non vanishing, the total U(1) ℓ charge, before picture changing, has to be an odd (even) number, for even (odd) order terms, respectively.…”

Section: Tools For Calculating the Fermion Mass Termsmentioning

confidence: 99%

“…In the context of superstring theory one can calculate the Yukawa couplings in terms of scattering amplitudes between the string states and certain VEVs that parameterize the string vacuum [4,5]. In their low energy limit superstring theories give rise to effective N = 1 supergravity [6].…”

Section: Introductionmentioning

confidence: 99%

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Calculating fermion masses in superstring derived standard-like models

Faraggi

1997

Nuclear Physics B

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One of the intriguing achievements of the superstring derived standard-like models in the free fermionic formulation is the possible explanation of the top quark mass hierarchy and the successful prediction of the top quark mass. An important property of the superstring derived standard-like models, which enhances their predictive power, is the existence of three and only three generations in the massless spectrum. Up to some motivated assumptions with regard to the light Higgs spectrum, it is then possible to calculate the fermion masses in terms of string tree level amplitudes and some VEVs that parameterize the string vacuum. I discuss the calculation of the heavy generation masses in the superstring derived standard-like models. The top quark Yukawa coupling is obtained from a cubic level mass term while the bottom quark and tau lepton mass terms are obtained from nonrenormalizable terms. The calculation of the heavy fermion Yukawa couplings is outlined in detail in a specific toy model. The dependence of the effective bottom quark and tau lepton Yukawa couplings on the flat directions at the string scale is examined. The gauge and Yukawa couplings are extrapolated from the string unification scale to low energies. Agreement with α strong , sin 2 θ W and α em at M Z is imposed, which necessitates the existence of intermediate matter thresholds. The needed intermediate matter thresholds exist in the specific toy model. The effect of the intermediate matter thresholds on the extrapolated Yukawa couplings in studied. It is observed that the intermediate matter thresholds also help to maintain the correct b/τ mass relation. It is found that for a large portion of the parameter space, the LEP precision data for α strong , sin 2 θ W and α em , as well as the top quark mass and the b/τ mass relation can all simultaneously be consistent with the superstring derived standard-like models. Possible corrections due to the supersymmetric mass spectrum are studied as well as the minimization of the supersymmetric Higgs potential. It is demonstrated that the calculated values of the Higgs VEV ratio, tan β = v 1 /v 2 , can be compatible with the minimization of the one-loop effective Higgs

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Section: Tools For Calculating the Fermion Mass Termsmentioning

confidence: 99%

Section: Tools For Calculating the Fermion Mass Termsmentioning

confidence: 99%

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Calculating fermion masses in superstring derived standard-like models

Faraggi

1997

Nuclear Physics B

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“…Trilinear and nonrenormalizable contributions to the superpotential are obtained by calculating corralators between vertex operators [13,14],…”

Section: Realistic Free Fermionic Modelsmentioning

confidence: 99%

Generation mass hierarchy in superstring derived models

Faraggi

1993

Nuclear Physics B

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I discuss the problem of generation mass hierarchy in the context of realistic superstring models which are constructed in the free fermionic formulation. These models correspond to models which are compactified on Z 2 × Z 2 orbifold. I suggest that the hierarchy among the generations results from horizontal symmetries, which arise from the compactification. In particular, I show that in a class of free fermionic standard-like models, the suppression of the mass terms for the lightest generation is a general, and unambiguous, characteristic of these models. I show that the mixing between the generations is suppressed due to the horizontal symmetries. I conclude that these models may potentially explain the generation mass hierarchy.

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“…V b n using the rules of Ref. (12). c n are numerical coefficients of O (1) These vanish in standard-like models [5] and we assume that they are not present in the following.…”

Section: Susy Breaking By Hidden Gaugino Condensationmentioning

confidence: 99%

Supersymmetry breaking by hidden matter condensation in superstrings

Halyo¹

1995

Physics Letters B

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We show that supersymmetry can be broken mainly by hidden matter condensates in the observable matter direction in generic superstring models. This happens only when the fields whose VEVs give masses to hidden matter do not decouple at the condensation scale. We find how the parameters of the string model and the vacuum determine whether supersymmetry is broken mainly by hidden matter or gaugino condensates and in the matter or moduli directions. † e-mail address: jphalyo@weizmann.bitnet 0

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Nonrenormalizable terms in the free fermionic formulation of 4D strings

Cited by 77 publications

References 52 publications

Calculating fermion masses in superstring derived standard-like models

Calculating fermion masses in superstring derived standard-like models

Generation mass hierarchy in superstring derived models

Supersymmetry breaking by hidden matter condensation in superstrings

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