Three Generations in Type I Compactifications

TL;DR

This paper classifies perturbative Type I string vacua on a specific orbifold, focusing on models with Standard Model gauge groups and three chiral families, highlighting their phenomenological features and challenges.

Contribution

It provides a comprehensive classification of Type I vacua with Standard Model gauge groups on a specific orbifold, including all possible Wilson lines, and analyzes their phenomenological implications.

Findings

All models contain D5-branes and are non-perturbative from the heterotic perspective.

Models feature three chiral families.

Identifies phenomenological challenges in these models.

Abstract

Generalizing the recent work on three-family Type I compactifications, we classify perturbative Type I vacua obtained via compactifying on the T^6/Z_2 X Z_2 X Z_3 orbifold with all possible Wilson lines. In particular, we concentrate on models with gauge groups containing the Standard Model gauge group SU(3)_c X SU(2)_w X U(1)_Y as a subgroup. All of the vacua we obtain contain D5-branes and are non-perturbative from the heterotic viewpoint. The models we discuss have three-chiral families. We study some of their phenomenological properties, and point out non-trivial problems arising in these models in the phenomenological context.