| dc.description |
We show the existence of realistic vacua in string theory whose observable sector has exactly the matter content of the MSSM. This is achieved by compactifying the E<sub>8</sub> × E<sub>8</sub> heterotic superstring on a smooth Calabi-Yau threefold with an SU(4) gauge instanton and a <sub>3</sub> × <sub>3</sub> Wilson line. Specifically, the observable sector is N = 1 supersymmetric with gauge group SU(3)<sub>C</sub> × SU(2)<sub>L</sub> × U(1)<sub>Y</sub> × U(1)<sub>B−L</sub>, three families of quarks and leptons, each family with a right-handed neutrino, and one Higgs–Higgs conjugate pair. Importantly, there are no extra vector-like pairs and no exotic matter in the zero mode spectrum. There are, in addition, 6 geometric moduli and 13 gauge instanton moduli in the observable sector. The holomorphic SU(4) vector bundle of the observable sector is slope-stable. |
