GUT Breaking on $M^4 \times T^2/(Z_2 \times Z_2^{\prime})$

TL;DR

This paper constructs SU(5) models on a specific orbifold space, breaking GUT symmetry to the Standard Model and addressing key issues like doublet-triplet splitting, hierarchy, and proton decay.

Contribution

It introduces two SU(5) models on $M^4 imes T^2/(Z_2 imes Z_2^{\

Findings

Achieves GUT symmetry breaking via orbifold projection.

Provides models with only Standard Model zero modes on the brane.

Addresses triplet-doublet splitting, hierarchy, and proton decay problems.

Abstract

We construct two SU(5) models on the space-time $M^4 \times T^2/(Z_2 \times Z_2^{\prime})$ where the gauge and Higgs fields are in the bulk and the Standard Model fermions are on the brane at the fixed point or line. For the zero modes, the SU(5) gauge symmetry is broken down to $SU(3) \times SU(2) \times U(1) $ due to non-trivil orbifold projection. In particular, if we put the Standard Model fermions on the 3-brane at the fixed point in Model II, we only have the zero modes and KK modes of the Standard Model gauge fields and two Higgs doublets on the observable 3-brane. So, we can have the low energy unification, and solve the triplet-doublet splitting problem, the gauge hierarchy problem, and the proton decay problem.