Standard-like models from Intersecting D5-branes

TL;DR

This paper constructs intersecting D5-brane models that replicate the Standard Model's gauge structure without supersymmetry, ensuring anomaly cancellation and realistic gauge coupling ratios, potentially near the electroweak scale.

Contribution

It presents a novel class of non-supersymmetric intersecting D5-brane orbifold models that reproduce the Standard Model spectrum and gauge couplings.

Findings

Models achieve Standard Model gauge group with vector-like matter.

Gauge coupling ratios are close to experimental values.

String scale can be near the electroweak scale.

Abstract

We construct intersecting D5-brane orbifold models that yield the (non-supersymmetric) standard model up to vector-like matter and charged-singlet scalars. The models are constrained by the requirement that twisted tadpoles cancel, and that the gauge boson coupled to the weak hypercharge $U(1)_Y$ does not get a string-scale mass via a generalised Green-Schwarz mechanism. Gauge coupling constant ratios close to those measured are easily obtained for reasonable values of the parameters, consistently with having the string scale close to the electroweak scale, as required to avoid the hierarchy problem.