`String Derived Exophobic SU(6) X SU(2) GUTs'

Free Fermionic construction is a model building technique in String Phenomenology, where we are able to 
discuss four dimensional theories using Heterotic Strings. Here we explore String derived SU(6) X SU(2) 
GUT models, where we show that it contains the required symmetry breaking Higgs representations. In 
addition the model also admits flat directions that produce a Yukawa coupling for a single family. The 
novel feature of the SU(6) × SU(2) string GUT models is that they produce an additional family universal 
anomaly free U(1) symmetry, and may remain unbroken below the string scale. Also the massless spectrum 
of the model is free of exotic states.