Universal torsion-induced interaction from large extra dimensions

Abstract

We consider the Kaluza–Klein (KK) scenario in which only gravity exists in the bulk. Without the assumption of symmetric connection, the presence of brane fermions induces torsion. The result is a universal axial contact interaction that dominates those induced by KK gravitons. This enhancement arises from a large spin density on the brane. Using a global fit to Z–pole observables, we find the 3σ bound on the scale of quantum gravity to be 28 TeV for n = 2. If Dirac or light sterile neutrinos are present, the data from SN1987A increase the bound to √n MS ≥ 210 TeV.