Kinetic mixing of U(1)s in heterotic orbifolds

Abstract

We study kinetic mixing between massless U(1) gauge symmetries in the bosonic formulation of heterotic orbifold compactifications. For non-prime Z N factorisable orbifolds, we find a simple expression of the mixing in terms of the properties of the N = 2 subsectors, which helps understand under what conditions mixing can occur. With this tool, we analyze Z 6-II heterotic orbifolds and find non-vanishing mixing even without including Wilson lines. We show that some semi-realistic models of the Mini-Landscape admit supersymmetric vacua with mixing between the hypercharge and an additional U(1), which can be broken at low energies. We finally discuss some phenomenologically appealing possibilities that hidden photons in heterotic orbifolds allow.