Standard-like models from D-branes

TL;DR

This paper explores intersecting D-brane orbifold models that can produce non-supersymmetric standard-like models, analyzing their features, scalar tachyons, Yukawa couplings, and gauge symmetries.

Contribution

It introduces new D4- and D5-brane orbifold models that realize the standard model with specific features like scalar tachyons and Yukawa couplings.

Findings

Six-stack D4-brane models with charged-singlet scalar tachyons

Models with Yukawa couplings to generate fermion masses

D5-brane models requiring at least eight stacks

Abstract

I describe the main features of new intersecting D4- and D5-brane orbifold models that yield the non-supersymmetric standard model, up to vector-like matter and, in some cases, extra U(1) factors in the gauge group. There are six-stack D4-brane models that have charged-singlet scalar tachyons and which either contain all of the Yukawa couplings to the tachyonic Higgs doublets that are needed to generate mass terms for the fermions at renormalisable level or possess an unwanted extra U(1) gauge symmetry after spontaneous symmetry breaking. In the D5-brane models a minimum of eight stacks is needed.