Z_2 x Z_2 Heterotic Orbifold Models of Non Factorisable Six Dimensional Toroidal Manifolds

TL;DR

This paper explores heterotic string models on non-factorisable six-tori orbifolds, highlighting the emergence of three-generation models with one per twisted sector and supporting the link between free fermionic points and Z_2 x Z_2 orbifolds.

Contribution

It introduces a new class of heterotic orbifold models on non-factorisable tori, demonstrating the natural occurrence of three-generation structures with minimal twisted sector content.

Findings

Reduced fixed tori compared to factorisable cases

Three-generation models with one per twisted sector

Support for the connection between free fermionic points and Z_2 x Z_2 orbifolds

Abstract

We discuss heterotic strings on Z_2 x Z_2 orbifolds of non factorisable six-tori. Although the number of fixed tori is reduced as compared to the factorisable case, Wilson lines are still needed for the construction of three generation models. An essential new feature is the straightforward appearance of three generation models with one generation per twisted sector. We illustrate our general arguments for the occurrence of that property by an explicit example. Our findings give further support for the conjecture that four dimensional heterotic strings formulated at the free fermionic point are related to Z_2 x Z_2 orbifolds.