E_8 flavour multiplets

TL;DR

This paper explores gauge symmetry enhancements to E8 on D7-branes, analyzing string configurations and supersymmetric Yang-Mills theory to understand how bound states form E8 multiplets.

Contribution

It provides a detailed analysis of E8 gauge symmetry enhancements on D7-branes using open string configurations and relates these to supersymmetric Yang-Mills theory.

Findings

Gauge symmetry enhancement to E8 on D7-branes is achieved.

Bound states of dyons and quarks form E8 multiplets.

String configurations relate to previous models by Gaberdiel and Zwiebach.

Abstract

We analyze gauge symmetry enhancements $SO(16)\to E_8$ on eight D7-branes and $SO(14)\times U(1)\to E_8$ on seven D7-branes from open strings. String configurations which we present in this paper are closely related to the ones given by Gaberdiel and Zwiebach. Our construction is based on $SO(8)\times SO(8)$ decomposition and its relation to the D8-brane case via T-duality is clearer. Then we study supersymmetric Yang-Mills theory on D3-brane near the D7-branes. This theory has flavour symmetry group which is equal to the gauge group on D7-branes. We suggest that when this symmetry is enhanced, two dyons make bound states which, together with elementary quarks, constitute an $E_8$ multiplet.