Chiral Asymmetry in Four-Dimensional Open-String Vacua

TL;DR

This paper constructs four-dimensional chiral open-string vacua with N=1 supersymmetry from type IIB string theory on a Z orbifold, exploring gauge groups, anomalies, and spectrum features relevant to string phenomenology.

Contribution

It introduces new chiral open-string vacua with specific gauge groups and spectra, analyzing anomaly cancellation and low-energy implications.

Findings

Largest gauge group: SO(8)xSU(12)xU(1)

Spectrum includes three chiral families

U(1) gauge boson acquires string-scale mass

Abstract

Starting from the type IIB string on the Z orbifold, we construct some chiral open-string vacua with N=1 supersymmetry in four dimensions. The Chan-Paton group depends on the (quantized) NS-NS antisymmetric tensor. The largest choice, SO(8)xSU(12)xU(1), has an anomalous U(1) factor whose gauge boson acquires a mass of the order of the string scale. The corresponding open-string spectrum comprises only Neumann strings and includes three families of chiral multiplets in the (8,12*) + (1,66) representation. A comparison is drawn with a heterotic vacuum with non-standard embedding, and some properties of the low-energy effective field theory are discussed.