Fabian Ruehle

A Z2xZ2 standard model

We present a Z_2 x Z_2 orbifold compactification of the E_8 x E_8 heterotic string which gives rise to the exact chiral MSSM spectrum. The GUT breaking SU(5) to SU(3)_C x SU(2)_L x U(1)_Y is realized by modding out a freely acting symmetry. This ensures precision gauge coupling unification. Further, it allows us to break the GUT group without switching on flux in hypercharge direction, such that the standard model gauge bosons can remain massless when the orbifold singularities are blown up. The model has vacuum configurations with matter parity, a large top Yukawa coupling and other phenomenologically appealing features.

Heterotic MSSM on a resolved orbifold

We construct an MSSM with three generations from the heterotic string compactified on a smooth 6D internal manifold using Abelian gauge uxes only. The compactification space is obtained as a resolution of the

Green-Schwarz mechanism in heterotic (2,0) gauged linear sigma models: torsion and NS5 branes

{{{{T^6}}} \left/ {{{\mathbb{Z}_2} \times {\mathbb{Z}_2} \times {\mathbb{Z}_{2,{\text{free}}}}}} \right.}

Non-Universal Anomalies in Heterotic String Constructions

orbifold. The

String theory and the dark glueball problem

{\mathbb{Z}_{2,{\text{free}}}}

Natural inflation and moduli stabilization in heterotic orbifolds

involution of such a resolution breaks the SU(5) GUT group down to the SM gauge group using a suitably chosen (freely acting) Wilson line. Surprisingly, the spectrum on a given resolution is larger than the one on the corresponding orbifold taking into account the branching and Higgsing due to the blow-up modes. The existence of extra resolution states is closely related to the fact that the resolution procedure is not unique. Rather, the various resolutions are connected to each other by op transitions.