5D Lorentz Violation as a Source of Soft Symmetry Breaking

Abstract

We suggest the possibility that soft symmetry breaking in low energy effective theories could be mediated by Kaluza‐Klein modes, in a 5‐dimensional theory with an explicitly broken SO(1,4) symmetry. To exemplify the mechanism, we present a toy model with a global SU(2) symmetry, which is classically exact at the zero mode level, but softly broken by radiative corrections induced from a single Lorentz violating term. We show that the Lorentz breaking parameter would set up the hierarchy between Planck scale and the breaking scale of the SU(2) effective theory.