A phenomenological study of 5d supersymmetry

Abstract

Supersymmetry and extra dimension need not be mutually exclusive options of physics for the TeV scale and beyond. Intrinsically higher dimensional top-down scenarios, e.g. string models, often contain supersymmetry at the weak scale. In this paper, we envisage a more phenomenological scenario by embedding the 4d constrained minimal supersymmetric standard model in a flat 5d S₁/Z₂ orbifold, with the inverse radius of compactification at the TeV scale. The gauge and Higgs supermultiplets are placed in the bulk. We assume that only the third generation matter multiplet accesses the bulk, while the first two generations are confined to a brane on an orbifold fixed point. From a 4d perspective, the bulk has N = 2 supersymmetry which entails a special non-renormalization theorem giving rise to a significant numerical impact on the renormalization group running of various parameters. The brane supersymmetry corresponds to N = 1 which we assume to be broken in an unspecified but phenomenologically acceptable way. Given this setup, we study how the gauge and Yukawa couplings and the N = 1 brane supersymmetry breaking soft masses run through the energy scale exciting the Kaluza-Klein states at regular interval. In the process, we ensure that electroweak symmetry does break radiatively. We confront our low energy parameters with the experimental measurements or limits of different observables, e.g. LEP lower limits on the lightest Higgs boson and the chargino, the (g - 2) of muon, the branching ratio of b → sγ, and the WMAP probe of relative dark matter abundance. We present our results by showing the allowed/disallowed zone in the plane of the common scalar mass (m₀) and common gaugino mass (M_1/2) for both positive and negative μ parameter. Our plots are the first 5d versions of the often displayed 4d m₀-M_1/2 plots, and we provide reasons behind the differences between the 4d and 5d plots.