Three family $Z_3$ orbifold trinification, MSSM and doublet-triplet splitting problem

Abstract

A $Z_3$ orbifold compactification of $E_8\times E_8^{\prime }$ heterotic string is considered toward a trinification $SU(3{)}^3$ with three light families. The GUT scale VEV's of the $SU(2{)}_W\times U(1{)}_Y\times SU(3{)}_c$ singlet chiral fields in two sets of the trinification spectrum allow an acceptable symmetry breaking pattern toward MSSM. We show that a doublet-triplet splitting is related to the absence of a $\Delta B$ nonzero operator.

Comments: Latex file of 13 pages