Standard Models and Split Supersymmetry from Intersecting Brane Orbifolds

Abstract

We construct four dimensional three generation non-supersymmetric $SU(3)_c \times SU(2)_L \times U(1)_Y$ intersecting D6-brane models with $\nu_R$\rq{s}. At three stacks we find exactly the MSSM chiral fermion matter spectrum. At 4-, 5-stacks we find models with the massless fermion spectrum of the N=1 Standard Model and massive exotic non-chiral matter; these models flow also to only the SM. At 8-stacks we find MSSM-like models, with minimal massless exotics, made from two different N=1 sectors. Exotic triplet masses put a lower bound on the string scale of $2.79/2.89 \times 10^6$ GeV for a Higgs 124/126 GeV. It\rq{}s the first appearance of N=0 stringy quivers with the MSSM and matter in antisymmetric representations and perturbatively missing Yukawa couplings. The present models are based on orientifolds of ${\bf T^6/(Z_3 \times Z_3)}$ compactifications of IIA theory based on the torus lattice AAA; all complex moduli are fixed by the orbifold symmetry. We also present the spectrum rules + GS anomaly cancellation for the ABB lattice. Moreover, we point out the relevance of intersecting/and present D6-brane constructions on ideas related to existence of split supersymmetry in nature. In this context we present non-susy models with only the SM-matter and also MSSM-matter dominated models, with massive gauginos and light higgsinos, that achieve the correct supersymmetric GUT value for the Weinberg angle $sin^2 \theta = \frac{3}{8}$ at a string scale $5 \cdot 10^{13} \ GeV < M_{S} < 1.4 \cdot 10^{17}$ GeV. It appears that if only the SM survives at low energy the unification scale is preserved at $5.03 \times 10^{13}$ GeV when n$_H$ =1, 3, 6. These models support the existence of split supersymmetry scenario in string theory.