Type IIA Pati-Salam Flux Vacua

TL;DR

This paper constructs supersymmetric AdS flux vacua in Type IIA orientifolds, enabling new intersecting D6-brane models that can generate realistic fermion masses, stabilize moduli, and break to the Standard Model gauge group.

Contribution

It introduces novel three-family Pati-Salam models with relaxed RR tadpole conditions and detailed mechanisms for fermion mass generation and gauge symmetry breaking.

Findings

Two types of models with realistic fermion masses are constructed.

Moduli stabilization is achieved through supersymmetric D6-brane configurations.

Gauge symmetry breaking down to the Standard Model is demonstrated.

Abstract

We show that for supersymmetric AdS vacua on Type IIA orientifolds with flux compactifications, the RR tadpole cancellation conditions can be completely relaxed, and then the four-dimensional N=1 supersymmetry conditions are the main constraints on consistent intersecting D6-brane model building. We construct two kinds of three-family Pati-Salam models. In the first kind of models, the suitable three-family SM fermion masses and mixings can be generated at the stringy tree level, and then the rank one problem for the SM fermion Yukawa matrices can be solved. In the second kind of models, only the third family of the SM fermions can obtain masses at tree level. In these models, the complex structure parameters can be determined by supersymmetric D6-brane configurations, and all the moduli may be stabilized. The initial gauge symmetries U(4)_C \times U(2)_L \times U(2)_R and U(4)_C \times USp(2)_L \times U(2)_R can be broken down to the SU(3)_C \times SU(2)_L \times U(1)_{B-L} \times U(1)_{I_{3R}} due to the Green-Schwarz mechanism and D6-brane splittings, and further down to the SM gauge symmetry around the string scale via the supersymmetry preserving Higgs mechanism. Comparing to the previous model building, we have less bidoublet Higgs fields. However, there generically exist some exotic particles.