2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/51912D4-D8 and D3-D7 systems are studied and a possible holographic dual of large N QCD (SU(N) gauge fields and fundamental quarks) is sought. A candidate system is found, for which however no explicit solution is available. Susy is broken by having a $D7-\bar{D7}$ condensing to a D5. The mechanism for supersymmetry breaking is then used to try to construct a Standard Model embedding. One can either obtain too few low energy fields or too many. The construction requires TeV scale string theory.42 pages, latexHigh Energy Physics - Theorytext