Supersymmetric extra dimensions: Gravitino effects in selectron pair production

Abstract

We examine the phenomenological consequences of a supersymmetric bulk in the scenario of large extra dimensions. We assume that supersymmetry is realized in the bulk and study the interactions of the resulting bulk gravitino Kaluza-Klein (KK) tower of states, with supersymmetry breaking on the brane inducing a light mass for the zero-mode gravitino. We derive the 4D effective theory, including the couplings of the bulk gravitino KK states to fermions and their scalar superpartners. The virtual exchange of the gravitino KK states in selectron pair production in polarized ${e}^{+}{e}^{\ensuremath{-}}$ collisions is then examined. We find that the leading order operator for this exchange is dimension 6, in contrast with that of bulk graviton KK exchange which induces a dimension 8 operator at lowest order. The resulting kinematic distributions for selectron production are dramatically altered from those in $D=4$ supersymmetric scenarios and can lead to an enormous sensitivity to the fundamental higher-dimensional Planck scale, of order $(20--25)\ifmmode\times\else\texttimes\fi{}\sqrt{s}.$