E8flavor multiplets

We analyze gauge symmetry enhancements $\mathrm{SO}\left(16\right)\mathrm{}\to E_8$ on eight D7-branes and $\mathrm{SO}\left(14\right)\mathrm{}\times U\left(1\right)\mathrm{}\to E_8$ on seven D7-branes from open strings. String configurations that we present in this paper are closely related to the ones given by Gaberdiel and Zwiebach. Our construction is based on $\mathrm{SO}\left(8\right)\mathrm{}\times \mathrm{SO}\left(8\right)\mathrm{}$ 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 a flavor symmetry group that is equal to the gauge group on D7-branes. We suggest that when this symmetry is enhanced, two dyons make bound states that, together with elementary quarks, constitute an $E_8$ multiplet.