COMPLETE STRUCTURE OF Z<sub>n</sub> YUKAWA COUPLINGS

Casas, J.A.; Gómez, F.; Muñoz, Carlos

doi:10.1142/s0217751x93000187

Cited by 76 publications

(108 citation statements)

References 18 publications

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“…2 )α ′ ), with α ′ the string slope parameter and c [36].) Naturally, the values at which these radii, or the corresponding overall modulus and anisotropies, settle is determined by compactification dynamics which lies outside the present framework.…”

Section: σ−Model Effective Actionmentioning

confidence: 99%

Flavor-changing neutral current constraints on standardlike orbifold models

Brax

Chemtob

1995

Phys. Rev. D

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We examine for standard-like orbifold compactification models the constraints due to quarks and leptons generation non-universality of soft supersymmetry breaking interactions. We follow the approach initiated by Ibáñez and Lüst and developed by Brignole, Ibáñez and Muñoz . This is based on a locally supersymmetric σ−model action of moduli and matter fields obeying the stringy duality symmetries. It is assumed that the low energy fields of the minimal supersymmetric standard model are in one-to-one correspondence with string massless modes and that supersymmetry breaking takes place simultaneously with the lifting of flat directions for dilaton and compactification moduli fields. The breaking of supersymmetry is represented in terms of dilaton and moduli auxiliary field components and, consistently with a vanishing cosmological constant, is parametrized in terms of the dilaton-moduli mixing angle θ and the gravitino mass scale m g . The soft supersymmetry breaking interactions (gaugino masses, squarks and sleptons mass matrices, scalars interactions A and B coupling constants) are calculable as a function of these parameters and of the discrete set of modular weight parameters specifying the modular transformation properties of the low energy fields. To establish the flavor changing neutral current constraints we solve the renormalization group one-loop equations for the full set of gauge, Yukawa and supersymmetry breaking coupling constants. A simplified version is used in which one treats the contributions from the third generation quarks and lepton Yukawa couplings exactly, while retaining for the first and second generations couplings only the leading order term in the large logarithm variable. Numerical results are obtained for the quantities ∆ M N = V Mm 2 M N V † N , corresponding to the mass matrices of squarks and sleptons in the super-CKM basis, for which experimental bounds can be determined via the super-box and super-penguin diagrams with gluino or neutralino exchange.

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Section: σ−Model Effective Actionmentioning

confidence: 99%

Flavor-changing neutral current constraints on standardlike orbifold models

Brax

Chemtob

1995

Phys. Rev. D

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“…(Useful information on these factors is provided in refs. [25,26]). For untwisted sectors (m = 0), there occurs corresponding non trivial factors χ(1, h) from the projection on oscillator states symmetric with respect to the orbifold point group.…”

Section: Classification Of Threshold Correctionsmentioning

confidence: 99%

“…where the compactification radius R and moduli VEV, < T >= T are related as T = C orb R 2 α ′ (2π) 2 , with C orb a calculable constant of order unity [26]. For, say, the Z 3 orbifold,…”

Section: Standard-like Superstring Unification Scenariomentioning

confidence: 99%

Threshold corrections in orbifold models and superstring unification of gauge interactions

Chemtob¹

1996

Phys. Rev. D

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The string one loop renormalization of the gauge coupling constants is examined in abelian orbifold models. The contributions to string threshold corrections independent of the compactification moduli fields are evaluated numerically for several representative examples of orbifold models. We consider cases with standard and non-standard embeddings as well as cases with discrete Wilson lines background fields which match reasonably well with low energy phenomenology. The gap separating the observed grand unified theories scale M GUT ≃ 2 × 10 16 GeV from the string unification scale M X ≃ 5 × 10 17 GeV is discussed on the basis of standard-like orbifold models. We examine one loop gauge coupling constants unification in a description incorporating the combined effects of moduli dependent and independent threshold corrections, an adjustable affine level for the hypercharge group factor and a large mass threshold associated with an anomalous U (1) mechanism.

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“…One the other hand, R charge conservation forbids couplings such as T (0,1) T (0,1) T (0,3) which share a common fixed torus [53].…”

Section: Hence For the Z 2 ×Z 4 Orbifold We Constructed There Is No mentioning

confidence: 99%

Lessons from model Buiding from the $Z_2\times Z_4$ orbifold

Mayorga-Pena¹,

Oehlmann²

2013

Proceedings of Proceedings of the Corfu Summer Institute 2012 — PoS(Corfu2012)

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We consider the key ingredients which made of the Z 6−II Mini-Landscape a successful ground for model building. There one observes a preferred distribution for the fields of the standard model which has direct implications on the phenomenology, since it favors a heavy top quark and a plausible solution to the µ-problem. We extend the exploration to the Z 2 × Z 4 orbifold, where a similar pattern is identified. To illustrate our findings we present an explicit Z 2 × Z 4 model that exhibits the MSSM spectrum plus vector-like exotics at the orbifold point. We take this construction as an example of a larger class of orbifold models which were anticipated at the GUT level. Furthermore we comment on VEV configurations to decouple the exotics while maintaining a meaningful R-symmetry which could forbid the µ-term.

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COMPLETE STRUCTURE OF Z_n YUKAWA COUPLINGS

Cited by 76 publications

References 18 publications

Flavor-changing neutral current constraints on standardlike orbifold models

Flavor-changing neutral current constraints on standardlike orbifold models

Threshold corrections in orbifold models and superstring unification of gauge interactions

Lessons from model Buiding from the $Z_2\times Z_4$ orbifold

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COMPLETE STRUCTURE OF Zn YUKAWA COUPLINGS

Cited by 76 publications

References 18 publications

Flavor-changing neutral current constraints on standardlike orbifold models

Flavor-changing neutral current constraints on standardlike orbifold models

Threshold corrections in orbifold models and superstring unification of gauge interactions

Lessons from model Buiding from the $Z_2\times Z_4$ orbifold

Contact Info

Product

Resources

About

COMPLETE STRUCTURE OF Z_n YUKAWA COUPLINGS