Deformations on Tilted Tori and Moduli Stabilisation at the Orbifold Point

Abstract

We discuss deformations of orbifold singularities on tilted tori in the context of Type IIA orientifold model building with D6-branes on special Lagrangian cycles. Starting from $T^6/({\mathbb{Z}}_2\times {\mathbb{Z}}_2)$, we mod out an additional ${\mathbb{Z}}_3$ symmetry to describe phenomenologically appealing backgrounds and reduce to ${\mathbb{Z}}_3$ and $\Omega \mathcal{R}$ invariant orbits of deformations. While D6-branes carrying SO(2N) or USp(2N) gauge groups do not constrain deformations, D6-branes with U(N) gauge groups develop non-vanishing D-terms if they couple to previously singular, now deformed cycles. We present examples for both types of D6-branes, and in a three-generation Pati-Salam model on $T^6/({\mathbb{Z}}_2\times {\mathbb{Z}}_6^{\prime })$ we find that ten out of 15 twisted complex structure moduli are indeed stabilised at the orbifold point by the existence of the brane stacks.

49 pages; v2: minor text-typo corrections, references added