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Intersecting brane world models from D8-branes on (T^2 x T^4/Z_3)/Omega R_1 type IIA orientifolds

Gabriele Honecker

TL;DR

This work constructs Type IIA orientifolds on $T^2\times T^4/\mathbb{Z}_3$ with D8-branes at angles, deriving RR and NSNS tadpole conditions and the resulting chiral open-string spectra. The models are T-dual to D4-brane setups with potential for large-volume compactifications, enabling a route to low string scales while yielding SM-like and left-right symmetric gauge sectors with chiral fermions. Mixed anomalies are canceled by a Green-Schwarz mechanism involving twisted RR fields, and NSNS tadpoles induce a moduli-dependent scalar potential, indicating stability challenges in these non-supersymmetric constructions. Four explicit examples illustrate the phenomenological prospects and the tight constraints from tadpoles, suggesting further exploration of more elaborate orbifolds or deformations to improve stability and chirality control.

Abstract

We present orientifold models of type IIA string theory with D8-branes compactified on a two torus times a four dimensional orbifold. The orientifold group is chosen such that one coordinate of the two torus is reversed when applying worldsheet parity. RR tadpole cancellation requires D8-branes which wrap 1-cycles on the two torus and transform non-trivially under the orbifold group. These models are T-dual to orientifolds with D4-branes only which admit large volume compactifications. The intersections of the D8-branes are chosen in such a way that supersymmetry is broken in the open string sector and chiral fermions arise. Stability of the models is discussed in the context of NSNS tadpoles. Two examples with the SM gauge group and two left-right symmetric models are given.

Intersecting brane world models from D8-branes on (T^2 x T^4/Z_3)/Omega R_1 type IIA orientifolds

TL;DR

This work constructs Type IIA orientifolds on with D8-branes at angles, deriving RR and NSNS tadpole conditions and the resulting chiral open-string spectra. The models are T-dual to D4-brane setups with potential for large-volume compactifications, enabling a route to low string scales while yielding SM-like and left-right symmetric gauge sectors with chiral fermions. Mixed anomalies are canceled by a Green-Schwarz mechanism involving twisted RR fields, and NSNS tadpoles induce a moduli-dependent scalar potential, indicating stability challenges in these non-supersymmetric constructions. Four explicit examples illustrate the phenomenological prospects and the tight constraints from tadpoles, suggesting further exploration of more elaborate orbifolds or deformations to improve stability and chirality control.

Abstract

We present orientifold models of type IIA string theory with D8-branes compactified on a two torus times a four dimensional orbifold. The orientifold group is chosen such that one coordinate of the two torus is reversed when applying worldsheet parity. RR tadpole cancellation requires D8-branes which wrap 1-cycles on the two torus and transform non-trivially under the orbifold group. These models are T-dual to orientifolds with D4-branes only which admit large volume compactifications. The intersections of the D8-branes are chosen in such a way that supersymmetry is broken in the open string sector and chiral fermions arise. Stability of the models is discussed in the context of NSNS tadpoles. Two examples with the SM gauge group and two left-right symmetric models are given.

Paper Structure

This paper contains 30 sections, 92 equations, 7 figures, 6 tables.

Table of Contents

  1. Introduction
  2. Construction of $(T^2\times T^4/Z_3)/\Omega {\mathcal{R}}_1$ Orientifolds
  3. General Setup
  4. RR-Tadpole Cancellation
  5. Klein bottle
  6. Annulus
  7. Möbius strip
  8. RR-tadpole cancellation
  9. Chiral open spectrum
  10. Cancellation of Mixed Anomalies
  11. NSNS tadpoles
  12. Example 1a: $SU(3)\times SU(2) \times U(1)^3$ and four generations
  13. Example 1b: $SU(3)\times SU(2) \times U(1)^2$ and four generations
  14. Example 2a: $SU(3)\times SU(2)_L\times SU(2)_R \times SO(8) \times U(1)^3$ and three generations
  15. Example 2b: $SU(3)\times SU(2)_L\times SU(2)_R \times SO(8) \times U(1)^2$ and three generations
  16. ...and 15 more sections

Figures (7)

  • Figure 1: a) Klein bottle, b) Annulus, c) Möbius strip
  • Figure 2: Green-Schwarz counter terms
  • Figure 3: Example 1a: Brane Configuration on $T_1$. The shaded area emphasises the fundamental cell of the torus. Solid lines denote D-branes, dotted lines denote their mirror images.
  • Figure 4: Example 1b: Brane Configuration on $T_1$
  • Figure 5: Example 2a: Brane Configuration on $T_1$
  • ...and 2 more figures