Exact standard model structures from intersecting D5-branes

Abstract We discuss the appearance of non-supersymmetric compactifications with exactly the Standard Model (SM) at low energies, in the context of IIB orientifold constructions with D5-branes intersecting at angles on the T 4 tori, of the orientifold of T 4 ×( C / Z N ). We discuss constructions where the Standard Model embedding is considering within four, five and six stacks of D5-branes. The appearance of the three generation observable Standard Model at low energies is accompanied by a gauged baryon number, thus ensuring automatic proton stability. Also, a compatibility with a low scale of order TeV is ensured by having a two-dimensional space transverse to all branes. The present models complete the discussion of some recently constructed four-stack models of D5-branes with the SM at low energy. By embedding the four-, five- and six-stack Standard Model configurations into quiver diagrams, deforming them around the QCD intersection numbers, we find a rich variety of vacua that may have exactly the Standard Model at low energy. Also by using brane recombination on the U (1)'s, we show that the five and six vacua flow into their four-stack counterparts. Thus string vacua with five- and six-stack deformations are continuously connected to the four-stack vacua.