Local SU(5) Unification in 6D from the Heterotic String

TL;DR

This paper constructs a six-dimensional orbifold model from heterotic string theory that naturally yields the Standard Model gauge group and matter content, with anomaly cancellation and split multiplets.

Contribution

It introduces a novel 6D orbifold compactification with local SU(5) unification and specific matter localization, advancing string-derived MSSM models.

Findings

Local gauge groups are SU(5) and SU(2)xSU(4) at fixed points

Anomaly cancellation achieved via Green-Schwarz mechanism

Standard Model matter arises from localized and split bulk multiplets

Abstract

We present a six-dimensional T^2/Z_2 orbifold model which arises as an intermediate step in the compactification of the heterotic string to the MSSM. The orbifold contains two pairs of inequivalent fixed points, with unbroken local gauge groups SU(5) and SU(2)xSU(4), respectively, the intersection of which gives the standard model gauge group. All bulk and brane anomalies are cancelled by the Green--Schwarz mechanism. At each SU(5) fixed point, there is a localised \bar{5}+10 standard model generation, while the third generation and the Higgs fields come in split bulk multiplets due to the breaking of SU(5) at the other fixed point.