Type $\bar{0}$ Heterotic String Orbifolds

Abstract

The $Z_2\times Z_2$ heterotic string orbifold gives rise to a large space of phenomenological three generation models that serves as a testing ground to explore how the Standard Model of particle physics may be incorporated in a theory of quantum gravity. Recently, we demonstrated the existence of type 0 $Z_2\times Z_2$ heterotic string orbifolds in which there are no massless fermionic states. In this paper we demonstrate the existence of non--supersymmetric tachyon--free $Z_2\times Z_2$ heterotic string orbifolds that do not contain any massless bosonic states from the twisted sectors. We dub these configurations type $\bar{0}$ models. They necessarily contain untwisted bosonic states, producing the gravitational, gauge and scalar moduli degrees of freedom, but possess an excess of massless fermionic states over bosonic ones, hence producing a positive cosmological constant. Such configurations may be instrumental when trying to understand the string dynamics in the early universe.

14 pages. Standard LaTeX. No figures. Published version

References in corpus (8)

• Towards a Non-Supersymmetric String Phenomenology
• Chiral family classification of fermionic Z2xZ2 heterotic orbifold models
• Chiral Heterotic Strings with Positive Cosmological Constant
• Top Quark Mass in Exophobic Pati--Salam Heterotic String Model
• Minimal Standard Heterotic String Models
• Classification of Flipped SU(5) Heterotic-String Vacua
• Stability, enhanced gauge symmetry and suppressed cosmological constant in 9D heterotic interpolating models
• On the Low Energy Spectra of the Nonsupersymmetric Heterotic String Theories

Cited by in corpus (2)

• Marginal deformations of heterotic interpolating models and exponential suppression of the cosmological constant
• Satisfiability Modulo Theories and Chiral Heterotic String Vacua with Positive Cosmological Constant