On the correlation of extra MSSM Higgs to stringent flat directions in heterotic string theory

It has been proposed that the number of extra copies of MSSM Higgs, as found in heterotically derived string GUT models, may be correlated to the existence and multiplicity of all-order stringent flat directions. We consider a handful of these GUT models and show that, even with a small number of MSSM Higgs, one can find all possibilities of flatness or lack thereof. Specifically, we present three flipped SU(5) and an SO(10) model and report on their respective D and F-flatness. We will report on each of the models' observable and hidden gauge content as well. Additionally, we comment on the possible relationship between flat direction phenomenology and moduli stabilization.