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79
Fourdimensional String Compactifications with DBranes, Orientifolds and Fluxes
"... This review article provides a pedagogical introduction into various classes of chiral string compactifications to four dimensions with Dbranes and fluxes. The main concern is to provide all necessary technical tools to explicitly construct fourdimensional orientifold vacua, with the final aim to ..."
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Cited by 147 (18 self)
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This review article provides a pedagogical introduction into various classes of chiral string compactifications to four dimensions with Dbranes and fluxes. The main concern is to provide all necessary technical tools to explicitly construct fourdimensional orientifold vacua, with the final aim to come as close as possible to the supersymmetric Standard Model. Furthermore, we outline the available methods to derive the resulting fourdimensional effective action. Finally, we summarize recent attempts to address the
Largevolume flux compactifications: Moduli spectrum and D3/D7 soft supersymmetry breaking
 SYSTEMATICS OF MODULI STABILISATION IN CALABIYAU FLUX COMPACTIFICATIONS,” JHEP 0503 (2005) 007 [ARXIV:HEPTH/0502058]. – 42
, 2005
"... We present an explicit calculation of the spectrum of a general class of string models, corresponding to CalabiYau flux compactifications with h1,2> h1,1> 1 with leading perturbative and nonperturbative corrections, in which all geometric moduli are stabilised as in hepth/0502058. The volum ..."
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Cited by 129 (20 self)
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We present an explicit calculation of the spectrum of a general class of string models, corresponding to CalabiYau flux compactifications with h1,2> h1,1> 1 with leading perturbative and nonperturbative corrections, in which all geometric moduli are stabilised as in hepth/0502058. The volume is exponentially large, leading to a range of string scales from the Planck mass to the TeV scale, realising for the first time the large extra dimensions scenario in string theory. We provide a general analysis of the relevance of perturbative and nonperturbative effects and the regime of validity of the effective field theory. We compute the spectrum in the moduli sector finding a hierarchy of masses depending on inverse powers of the volume. We also compute soft supersymmetry breaking terms for particles living on D3 and D7 branes. We find a hierarchy of soft terms corresponding to ‘volume dominated ’ Fterm supersymmetry breaking. Fterms for Kähler moduli dominate both those for dilaton and complex
Flux–induced Soft Supersymmetry Breaking in Chiral Type IIB Orientifolds with D3/D7–Branes
, 2004
"... We discuss supersymmetry breaking via 3–form fluxes in chiral supersymmetric type IIB orientifold vacua with D3 – and D7–branes. After a general discussion of possible choices of fluxes allowing for stabilizing of a part of the moduli, we determine the resulting effective action including all soft s ..."
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Cited by 79 (8 self)
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We discuss supersymmetry breaking via 3–form fluxes in chiral supersymmetric type IIB orientifold vacua with D3 – and D7–branes. After a general discussion of possible choices of fluxes allowing for stabilizing of a part of the moduli, we determine the resulting effective action including all soft supersymmetry breaking terms. We also extend the computation of our previous work [1] concerning the matter field metrics arising from various open string sectors, in particular focusing on the 1/2 BPS D3/D7–brane configuration. Afterwards, the F–theory lift of our constructions is investigated
One in a billion: MSSMlike Dbrane statistics
, 2005
"... Continuing our recent work hepth/0411173, we study the statistics of fourdimensional, supersymmetric intersecting Dbrane models in a toroidal orientifold background. We have performed a vast computer survey of solutions to the stringy consistency conditions and present their statistical implicatio ..."
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Cited by 66 (18 self)
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Continuing our recent work hepth/0411173, we study the statistics of fourdimensional, supersymmetric intersecting Dbrane models in a toroidal orientifold background. We have performed a vast computer survey of solutions to the stringy consistency conditions and present their statistical implications with special emphasis on the frequency of Standard Model features. Among the topics we discuss are the implications of the Ktheory constraints, statistical correlations among physical quantities and an investigation of the various statistical suppression factors arising once certain Standard Model features are required. We estimate the frequency of an MSSM like gauge group with three generations to be one in a billion.
Nonperturbative superpotentials in Ftheory and string duality
, 2005
"... We use openclosed string duality between Ftheory on K3 × K3 and type II strings on CY manifolds without branes to study nonperturbative superpotentials in generalized flux compactifications. On the Ftheory side we obtain the full flux potential including D3instanton contributions and show that ..."
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Cited by 45 (2 self)
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We use openclosed string duality between Ftheory on K3 × K3 and type II strings on CY manifolds without branes to study nonperturbative superpotentials in generalized flux compactifications. On the Ftheory side we obtain the full flux potential including D3instanton contributions and show that it leads to an explicit and simple realization of the three ingredients of the KKLT model for stringy dS vacua. The D3instanton contribution is highly nontrivial, can be systematically computed including the determinant factors and demonstrates that a particular flux lifts very effectively zero modes on the instanton. On the closed string side, we describe a generalization of the GukovVafaWitten superpotential for type II strings on generalized CY manifolds, depending on all moduli multiplets.
Generalized nonsupersymmetric flux vacua
, 2008
"... We discuss a novel strategy to construct 4D N = 0 stable flux vacua of type II string theory, based on the existence of BPS bounds for probe Dbranes in some of these backgrounds. In particular, we consider compactifications where Dbranes filling the 4D spacetime obey the same BPS bound as they ..."
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Cited by 45 (11 self)
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We discuss a novel strategy to construct 4D N = 0 stable flux vacua of type II string theory, based on the existence of BPS bounds for probe Dbranes in some of these backgrounds. In particular, we consider compactifications where Dbranes filling the 4D spacetime obey the same BPS bound as they would in an N = 1 compactification, while other Dbranes, like those appearing as domain walls from the 4D perspective, can no longer be BPS. We construct a subfamily of such backgrounds giving rise to 4D N = 0 Minkowski noscale vacua, generalizing the wellknown case of type IIB on a warped CalabiYau. We provide several explicit examples of these constructions, and compute quantities of phenomenological interest like fluxinduced soft terms on Dbranes. Our results have a natural, simple description in the language of Generalized Complex Geometry, and in particular in terms of Dbrane generalized calibrations. Finally, we extend the integrability theorems for 10D supersymmetric type II backgrounds to the N = 0 case and use the results to construct a new class of N = 0 AdS4 compactifications.
MSSM with Soft SUSY Breaking Terms from D7–Branes with Fluxes
, 2004
"... We discuss the structure of the soft supersymmetry breaking terms in a MSSM like model, which can be derived from D7–branes with chiral matter fields from 2–form f–fluxes and supersymmetry breaking from ..."
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Cited by 44 (7 self)
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We discuss the structure of the soft supersymmetry breaking terms in a MSSM like model, which can be derived from D7–branes with chiral matter fields from 2–form f–fluxes and supersymmetry breaking from
Fractional Branes and Dynamical Supersymmetry Breaking
, 2005
"... We study the dynamics of fractional branes at toric singularities, including cones over del Pezzo surfaces and the recently constructed Y p,q theories. We find that generically the field theories on such fractional branes show dynamical supersymmetry breaking, due to the appearance of nonperturba ..."
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Cited by 43 (6 self)
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We study the dynamics of fractional branes at toric singularities, including cones over del Pezzo surfaces and the recently constructed Y p,q theories. We find that generically the field theories on such fractional branes show dynamical supersymmetry breaking, due to the appearance of nonperturbative superpotentials. In special cases, one recovers the known cases of supersymmetric infrared behaviors, associated to SYM confinement (mapped to complex deformations of the dual geometries, in the gauge/string correspondence sense) or N = 2 fractional branes. In the supersymmetry breaking cases, when the dynamics of closed string moduli at the singularity is included, the theories show a runaway behavior (involving moduli such as FI terms or equivalently dibaryonic operators), rather than stable nonsupersymmetric minima. We comment on the implications of this gauge theory behavior for the infrared smoothing of the dual warped throat solutions with 3form fluxes, describing duality cascades ending in such field theories. We finally provide a description of the different fractional branes in the recently introduced brane tiling configurations.
The effective action of N = 1 CalabiYau orientifolds
, 2004
"... We determine the N = 1 low energy effective action for compactifications of type IIB string theory on compact CalabiYau orientifolds in the presence of background fluxes from a KaluzaKlein reduction. The analysis is performed for CalabiYau threefolds which admit an isometric and holomorphic invol ..."
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Cited by 39 (6 self)
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We determine the N = 1 low energy effective action for compactifications of type IIB string theory on compact CalabiYau orientifolds in the presence of background fluxes from a KaluzaKlein reduction. The analysis is performed for CalabiYau threefolds which admit an isometric and holomorphic involution. We explicitly compute the Kähler potential, the superpotential and the gauge kinetic functions and check the consistency with N = 1 supergravity. We find a new class of noscale Kähler potentials and show that their structure can be best understood in terms of a dual formulation where some of the chiral multiplets are replaced by linear multiplets. For O3 and O7planes the scalar potential is expressed in terms of a superpotential while for O5 and O9planes also a Dterm and a massive linear multiplet can be present. The relation with the associated Ftheory compactifications is briefly discussed. In recent years it became clear that string theory is not only a theory of fundamental strings but also contains higherdimensional extended objects such as Dbranes and orientifold
The D5brane effective action and superpotential in N = 1 Compactifications
, 2008
"... The fourdimensional effective action for D5branes in generic compact CalabiYau orientifolds is computed by performing a KaluzaKlein reduction. The N = 1 Kähler potential, the superpotential, the gaugekinetic coupling function and the Dterms are derived in terms of the geometric data of the int ..."
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Cited by 37 (4 self)
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The fourdimensional effective action for D5branes in generic compact CalabiYau orientifolds is computed by performing a KaluzaKlein reduction. The N = 1 Kähler potential, the superpotential, the gaugekinetic coupling function and the Dterms are derived in terms of the geometric data of the internal space and of the twocycle wrapped by the D5brane. In particular, we obtain the D5brane and flux superpotential by integrating out fourdimensional threeforms which couple via the ChernSimons action. Also the infinitesimal complex structure deformations of the twocycle induced by the deformations of the ambient space contribute to the Fterms. The superpotential can be expressed in terms of relative periods depending on both the open and closed moduli. To analyze this dependence we blow up along the twocycle and obtain a rigid divisor in an auxiliary compact threefold with negative first Chern class. The variation of the mixed Hodge structure on this blownup geometry is equivalent to the original deformation problem and can be analyzed by PicardFuchs equations. We exemplify the blowup procedure for a noncompact CalabiYau threefold given by the canonical bundle over del Pezzo surfaces.