In this talk I outline work done in collaboration with R.J. Zhang and T.
Kobayashi. We show how to construct the equivalent of three family orbifold
GUTs in five dimensions from the heterotic string. I focus on one particular
model with E(6) gauge symmetry in 5D, the third family and Higgs doublet coming
from the 5D bulk and the first two families living on 4D SO(10) branes. Note
the E(6) gauge symmetry is broken to Pati-Salam in 4D which subsequently breaks
to the Standard Model gauge symmetry via the Higgs mechanism. The model has two
flaws, one fatal and one perhaps only unaesthetic. The model has a small set of
vector-like exotics with fractional electromagnetic charge. Unfortunately not
all of these states obtain mass at the compactification scale. This flaw is
fatal. The second problem is R parity violating interactions. These problems
may be avoidable in alternate orbifold compactification schemes. It is these
problems which we discuss in this talk.Comment: 5 pages, 6 figures, plenary talk given at PASCOS 2005, May 30 - June
4, Gyeongju, Kore
