Improved bounds on universal extra dimensions and consequences for Kaluza-Klein dark matter

Abstract

We study constraints on models with a flat universal extra dimension in which all standard model fields propagate in the bulk. A significantly improved constraint on the compactification scale is obtained from the extended set of electroweak precision observables accurately measured at LEP1 and LEP2. We find a lower bound of ${M}_{c}\ensuremath{\equiv}{R}^{\ensuremath{-}1}>700(800)\text{ }\text{ }\mathrm{GeV}$ at the 99% (95%) confidence level. We also discuss the implications of this constraint on the prospects for the direct and indirect detection of Kaluza-Klein dark matter in this model.