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114
MODELS OF PARTICLE PHYSICS FROM TYPE IIB STRING THEORY AND F-THEORY: A REVIEW
, 2012
"... We review particle physics model building in type IIB string theory and F-theory. This is a region in the landscape where in principle many of the key ingredients required for a realistic model of particle physics can be combined successfully. We begin by reviewing moduli stabilisation within this f ..."
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Cited by 33 (4 self)
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We review particle physics model building in type IIB string theory and F-theory. This is a region in the landscape where in principle many of the key ingredients required for a realistic model of particle physics can be combined successfully. We begin by reviewing moduli stabilisation within this framework and its implications for supersymmetry breaking. We then review model building tools and developments in the weakly coupled type IIB limit, for both local D3-branes at singularities and global models of intersecting D7-branes. Much of recent model building work has been in the strongly coupled regime of F-theory due to the presence of exceptional symmetries which allow for the construction of phenomenologically appealing Grand Unified Theories. We review both local and global F-theory model building starting from the fundamental concepts and tools regarding how the gauge group, matter sector and operators arise, and ranging to detailed phenomenological properties explored in the literature.
Dirac Action On M5 and M2 Branes with Bulk Fluxes
, 2005
"... We derive an explicit form of the quadratic-in-fermions Dirac action on the M5 brane for an arbitrary on-shell background of 11D supergravity with non-vanishing fluxes and in presence of a chiral 2-form on M5. This action may be used to generalize the conditions for which the non-perturbative superp ..."
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Cited by 27 (5 self)
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We derive an explicit form of the quadratic-in-fermions Dirac action on the M5 brane for an arbitrary on-shell background of 11D supergravity with non-vanishing fluxes and in presence of a chiral 2-form on M5. This action may be used to generalize the conditions for which the non-perturbative superpotential can be generated in M/string theory. We also derive the Dirac action with bulk fluxes on the M2 brane.
New F-theory lifts
"... Abstract: In this note, a procedure is developed to explicitly construct non-trivial F-theory lifts of perturbative IIB models on toric Calabi-Yau orientifolds. This procedure works on Calabi-Yau orientifolds where the involution coordinate can have arbitrary projective weight, as opposed to the wel ..."
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Cited by 26 (1 self)
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Abstract: In this note, a procedure is developed to explicitly construct non-trivial F-theory lifts of perturbative IIB models on toric Calabi-Yau orientifolds. This procedure works on Calabi-Yau orientifolds where the involution coordinate can have arbitrary projective weight, as opposed to the well-known cases where it has half the weight of the hypersurface equation defining the CY threefold. This opens up the possibility of lifting more general setups, such as models that have O3-planes. Contents
Computational complexity of the landscape
- I
"... Abstract: We study the computational complexity of the physical problem of finding vacua of string theory which agree with data, such as the cosmological constant, and show that such problems are typically NP hard. In particular, we prove that in the Bousso-Polchinski model, the problem is NP comple ..."
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Cited by 25 (2 self)
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Abstract: We study the computational complexity of the physical problem of finding vacua of string theory which agree with data, such as the cosmological constant, and show that such problems are typically NP hard. In particular, we prove that in the Bousso-Polchinski model, the problem is NP complete. We discuss the issues this raises and the possibility that, even if we were to find compelling evidence that some vacuum of string theory describes our universe, we might never be able to find that vacuum explicitly. In a companion paper, we apply this point of view to the question of how early cosmology might select a vacuum. Contents
Realistic Yukawa structures from orientifold compactifications
, 2009
"... We perform a systematic analysis of globally consistent D-brane quivers which realize the MSSM and analyze them with respect to their Yukawa couplings. Often, desired couplings are perturbatively forbidden due to the presence of global U(1) symmetries. We investigate the conditions under which D-bra ..."
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Cited by 25 (10 self)
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We perform a systematic analysis of globally consistent D-brane quivers which realize the MSSM and analyze them with respect to their Yukawa couplings. Often, desired couplings are perturbatively forbidden due to the presence of global U(1) symmetries. We investigate the conditions under which D-brane instantons will induce these missing couplings without generating other phenomenological drawbacks, such as R-parity violating couplings or a µ-term which is too large. Furthermore, we systematically analyze which quivers allow for a mechanism that can account for the small neutrino masses and other experimentally observed hierarchies. We show that only a small fraction of the globally consistent D-brane quivers
General Analysis of LARGE Volume Scenarios with String Loop Moduli Stabilisation,” 0805.1029
"... Abstract: We study the topological conditions for general Calabi-Yaus to get a nonsupersymmetric AdS exponentially large volume minimum of the scalar potential in flux compactifications of IIB string theory. We show that negative Euler number and the existence of at least one blow-up mode resolving ..."
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Cited by 23 (3 self)
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Abstract: We study the topological conditions for general Calabi-Yaus to get a nonsupersymmetric AdS exponentially large volume minimum of the scalar potential in flux compactifications of IIB string theory. We show that negative Euler number and the existence of at least one blow-up mode resolving point-like singularities are necessary and sufficient conditions for moduli stabilisation with exponentially large volumes. We also analyse the general effects of string loop corrections on this scenario. While the combination of α ′ and nonperturbative corrections are sufficient to stabilise blow-up modes and the overall volume, quantum corrections are needed to stabilise other directions transverse to the overall volume. This allows exponentially large volume minima to be realised for fibration Calabi-Yaus, with the various moduli of the fibration all being stabilised at exponentially large values. String loop corrections may also play a role in stabilising 4-cycles which support chiral matter and cannot enter directly into the non-perturbative superpotential. We illustrate these ideas by studying the scalar potential for various Calabi-Yau three-folds including K3 fibrations and briefly discuss the potential phenomenological and
Toric K3-Fibred Calabi-Yau Manifolds with del Pezzo Divisors for String Compactifications
- JHEP 1202 (2012) 002, ARXIV:1107.0383 [HEP-TH
, 2012
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General type IIB fluxes with SU(3) structures
- Nucl. Phys. B
"... A supersymmetric vacuum has to obey a set of constraints on fluxes as well as first order differential equations defined by the G-structures of the internal manifold. We solve these equations for type IIB supergravity with SU(3) structures. The 6-dimensional internal manifold has to be complex, the ..."
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Cited by 21 (1 self)
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A supersymmetric vacuum has to obey a set of constraints on fluxes as well as first order differential equations defined by the G-structures of the internal manifold. We solve these equations for type IIB supergravity with SU(3) structures. The 6-dimensional internal manifold has to be complex, the axion/dilaton is in general non-holomorphic and a cosmological constant is only possible if the SU(3) structures are broken to SU(2) structures. The general solution is expressed in terms of one function which is holomorphic in the three complex coordinates and if this holomorphic function is constant, we obtain a flow-type solution and near poles and zeros we
D-terms and F-terms from D7-brane fluxes
, 2005
"... Using a Kaluza-Klein reduction of the fermionic part of the D-brane action we compute D- and F-terms of the N = 1 effective action for generic Calabi-Yau orientifold compactifications in the presence of a space-time filling D7-brane. We include non-trivial background fluxes for the D7-brane U(1) fie ..."
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Cited by 20 (2 self)
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Using a Kaluza-Klein reduction of the fermionic part of the D-brane action we compute D- and F-terms of the N = 1 effective action for generic Calabi-Yau orientifold compactifications in the presence of a space-time filling D7-brane. We include non-trivial background fluxes for the D7-brane U(1) field strength on the internal four-cycle wrapped by the brane. First the four-dimensional fermionic spectrum arising from the D7-brane is derived and then the D- and F-terms are obtained by computing appropriate couplings of these fermionic fields. For specific examples we examine the resulting flux-induced scalar potentials and comment on their relevance in string cosmology.
