Standard-like Models as Type IIB Flux Vacua

TL;DR

This work constructs explicit Type IIB flux vacua on Z2×Z2 orientifolds with magnetized D-branes to realize SM-like spectra. By incorporating magnetized D9-branes carrying large negative D3-charge within the SM sector, it overcomes RR tadpole constraints and generates extensive classes of three- and four-family vacua with up to three units of supersymmetric flux, achieving stabilization of complex structure and dilaton, and often fixing all toroidal Kähler moduli. The study also explores non-supersymmetric fluxes and KKLT-like stabilization via D7-brane gauge dynamics, providing detailed brane configurations and spectra, and discusses Yukawa couplings and chiral exotics. Together, these results advance the construction of realistic string vacua with partial moduli stabilization and point to avenues for complete stabilization and phenomenological viability.

Abstract

We construct new semi-realistic Type IIB flux vacua on $Z_2\times Z_2$ orientifolds with three- and four- Standard Model (SM) families and up to three units of quantized flux. The open-string sector is comprised of magnetized D-branes and is T-dual to supersymmetric intersecting D6-brane constructions. The SM sector contains magnetized D9-branes with negative D3-brane charge contribution. There are large classes of such models and we present explicit constructions for representative ones. In addition to models with one and two units of quantized flux, we also construct the first three- and four-family Standard-like models with supersymmetric fluxes, i.e. comprising three units of quantized flux. Supergravity fluxes are due to the self-dual NS-NS and R-R three-form field strength and they fix the toroidal complex structure moduli and the dilaton. The supersymmetry conditions for the D-brane sector fix in some models all three toroidal Kähler moduli. We also provide examples where toroidal K\" ahler moduli are fixed by strong gauge dynamics on the ``hidden sector'' D7-brane. Most of the models possess Higgs doublet pairs with Yukawa couplings that can generate masses for quarks and leptons. The models have (mainly right-) chiral exotics.