Intersecting branes flip SU(5)

Within a toroidal oibifold framework, we exhibit intersecting brane-world constructions of flipped SU(5) x U(1) GUT models with various numbers of generations, other chiral matter representations and Higgs representations. We exhibit orientifold constructions with integer winding numbers that yield 8 or more conventional SU(5) generations, and orbifold constructions with fractional winding numbers that yield flipped SU(5) x U(1) models with just 3 conventional generations. Some of these models have candidates for the 5 and Higgs representations needed for electroweak symmetry breaking, but not for the 10 and (10) over bar representations needed for GUT symmetry breaking. We have also derived models with complete GUT and electroweak Higgs sectors, but these have undesirable extra chiral matter. (C) 2002 Elsevier Science B.V. All rights reserved.