N=1 Supersymmetric Standard Models from Intersecting Branes (original) (raw)

We construct the first examples of four dimensional three generation N=1 supersymmetric SU(3)cotimesSU(2)LotimesU(1)YSU(3)_c \otimes SU(2)_L \otimes U(1)_YSU(3)cotimesSU(2)LotimesU(1)Y intersecting D6-brane models, that have the spectrum of the N=1 supersymmetric SM and have only a minimal number of (four) massless exotics that constitute a non-chiral set and also have all complex structure moduli naturally fixed by the orbifold symmetry. These models are based on orientifolds of bfT6/(Z3timesZ3){\bf T^6/(Z_3 \times Z_3)}bfT6/(Z3timesZ3) compactifications of IIA theory. The full spectrum of the three generation models accommodates also nuRc\nu_R^cnuRc's and three pairs of MSSM Higgs multiplets. Baryon number is not gauged but as the string scale is geometrically close to the Planck scale proton stability and a solution to the gauge hierarchy problem is guaranteed. A superpotential mu\mumu-term is always present. We also find three stack non-supersymmetric vacua with only the chiral spectrum and gauge group of the SM and no exotics, that possess a N=1 SUSY sector associated with the nuRc\nu_R^cnuRc's which is being used to break the extra U(1) surviving massless the GS mechanism. Also we find five stack non-supersymmetric vacua with exactly the massless chiral spectrum of the N=1 Standard Model + exotic matter, which using tachyonic Higgs excitations flow to only the SM. We point out that in all constructions there is no tree level mass term for the up-quarks.