Bulk standard model in the Randall-Sundrum background - art. no. 084025

We discuss issues in an attempt to put the standard model (SM) in five-dime nsional anti-de Sitter spacetime compactified on S-1/Z(2). The recently pro posed approach to the gauge hierarchy problem by using this background geom etry, with the SM confined on a boundary, is extended to a situation where (some of) the SM particles reside in the five-dimensional bulk. In particul ar, we find a localization of zero modes of bulk fermions near the boundary with a negative tension. Unlike the compactification with the fat metric, these fermion zero modes couple to Kaluza-Klein (KK) excitations of the SM gauge bosons;Interestingly, only low-lying modes of such KK gauge bosons ha ve non-negligible couplings. Current electroweak precision data give a cons traint that the first KK mode be heavier than 9 TeV. We also argue that at least the Higgs field should be confined on the brane to utilize the Randal l-Sundrum background as a solution to the gauge hierarchy.