Chiral D-brane Models with Frozen Open String Moduli

Abstract

Most intersecting D-brane vacua in the literature contain additional massless adjoint fields in their low energy spectrum. The existence of these additional fields make it difficult to obtain negative beta functions and, eventually, asymptotic freedom. We address this important issue for N = 1 intersecting D-brane models, rephrasing the problems in terms of (open string) moduli stabilization. In particular, we consider a Z 2 × Z 2 orientifold construction where D6-branes wrap rigid 3-cycles and such extra adjoint fields do not arise. We derive the model building rules and consistency conditions for intersecting branes in this background, and provide N = 1 chiral vacua free of adjoint fields. More precisely, we construct a Pati-Salam-like model whose SU (4) gauge group is asymptotically free. We also comment on the application of these results for obtaining gaugino condensation in chiral D-brane models. Finally, we embed our constructions in the framework of flux compactification, and construct new classes of N = 1 and N = 0 chiral flux vacua. † Permanent address

Rigid D6-branes on $ {{{{T^6}}} \left/ {{\left( {{Z_2} \times {Z_{2M}} \times \Omega \mathcal{R}} \right)}} \right.} $ with discrete torsion

“…Our arguments follow [82,33]. An ΩR eigenvalue appears in the loop channel and can be ±1 since (ΩR) 2 = 1.…”

“…So, turning on discrete torsion changes sign of one of the O6-plane charges on the lhs of (13). Denoting the extra sign of an O6-plane charge by eta with its crosscap map as a subscript we can summarise the situation as [33] …”

“…Since D6-branes wrapping such cycles cannot change position (at least in some direction) the corresponding adjoint moduli are absent from the open string spectrum. (However, for 2M > 2 adjoints can "reappear through the back-door" from open strings stretching to intersecting orbifold images [33,34]. In that case adjoint moduli are associated with brane recombination.…”

“…In [50,51,33] the case 2M = 2 (Z 2 × Z 2 ) was studied and toy models with removed adjoint moduli were presented. 2 Another, empirical, observation favouring the discrete torsion orbifolds has been made in [57]: In cases where there are no three family models without discrete torsion (viz.…”

One in a billion: MSSM-like D-brane statistics

“…More concretely, we study supersymmetric intersecting D-brane models on the T 6 Z 2 ×Z 2 orientifold background, which has enjoyed great interest in the past (see e.g. [37][38][39][40][41] among many others). We consider the ensemble of solutions to the tadpole cancellation conditions using 1 Criticism of the landscape idea is expressed in [24,25].…”