SU(5) Unified Theories from Intersecting Branes

Abstract

We discuss the first string theory examples of three generation non-supersymmetric SU(5) and {\em flipped} SU(5) GUTS, which break to the Standard model at low energy, without extra matter and/or gauge group factors. Our GUT examples are based on IIA $Z_3$ orientifolds with D6-branes intersecting at non-trivial angles. These theories necessarily satisfy RR tadpoles and are free of NSNS tadpoles as the complex structure moduli are frozen (even though a dilaton tadpole remains) to discrete values. We identify appropriately the bifundamental Higgses responsible for electroweak symmetry breaking. In this way, the neutrino see-saw mechanism get nicely realized in these constructions. Moreover, as baryon number is not a gauged symmetry gauge mediated dimension six operators do contribute to proton decay; however proton lifetime may be safely enhanced by appropriately choosing a high GUT scale. An accompanying natural doublet-triplet splitting guarantees the suppression of scalar mediated proton decay modes and the stability of triplet scalar masses against higher dimensional non-renormalizable operators.

26 pages, 5 figures; no changes, one comment added in the introduction

References in corpus (9)

• Reduction of one-loop tensor 5-point integrals
• Yukawa couplings in intersecting D-brane models
• Conformal Field Theory Couplings for Intersecting D-branes on Orientifolds
• Proton Decay in Intersecting D-brane Models
• Magnetized Four-Dimensional $Z_2\times Z_2$ Orientifolds
• Recombination of Intersecting D-branes by Local Tachyon Condensation
• Flavour Changing Neutral Currents in Intersecting Brane Models
• Recombination of Intersecting D-branes in Tachyon Field Theory
• Linearized Gravity in the Karch-Randall Braneworld

Cited by in corpus (27)

• Four-dimensional String Compactifications with D-Branes, Orientifolds and Fluxes
• Toward Realistic Intersecting D-Brane Models
• Proton stability in grand unified theories, in strings, and in branes
• Intersecting Brane Worlds -- A Path to the Standard Model ?
• Orientifolds, hypercharge embeddings and the Standard Model
• Brane world effective actions for D-branes with fluxes
• D-branes in Standard Model building, Gravity and Cosmology
• Internal magnetic fields and supersymmetry in orientifolds
• Discrete Gauge Symmetries in Discrete MSSM-like Orientifolds
• Flavour in Intersecting Brane Models and Bounds on the String Scale
• SU(5) orientifolds, Yukawa couplings, Stringy Instantons and Proton Decay
• Scherk-Schwarz Breaking and Intersecting Branes
• Proton decay via dimension-six operators in intersecting D6-brane models
• Statistics of SU(5) D-Brane Models on a Type II Orientifold
• Bounds on Four-Fermion Contact Interactions Induced by String Resonances
• Properties of Fermion Mixings in Intersecting D-brane Models
• Standard Model Compactifications of IIA Z3 x Z3 Orientifolds from Intersecting D6-branes
• Orientifold's Landscape: Non-Factorisable Six-Tori
• Higher Dimensional Recombination of Intersecting D-branes
• Gauge sector statistics of intersecting D-brane models
• Stringent Phenomenological Investigation into Heterotic String Optical Unification
• Note on a NAHE Variation
• MSSM via Pati-Salam from Intersecting Branes on $T^6/({\mathbb{Z}}_2\times {\mathbb{Z}}_2^{\prime })$
• Remarks on Limits on String Scale from Proton Decay and Low-Energy amplitudes in Braneworld Scenario
• Nucleon decay in gauge unified models with intersecting D6-branes
• Realistic Four-Generation MSSM in Type II String Theory
• TeV-Scale Stringy Signatures at the Electron-positron Collider