We consider the Kaluza-Klein scenario in which gravity propagates in the $\mathrm{}(4+n)\mathrm{}$-dimensional bulk of spacetime and the standard model particles are confined to a 3-brane. We calculate the gauge boson self-energy corrections arising from the exchange of virtual gravitons and present our results in the $\mathrm{STU}$ formalism. We find that the new physics contributions to S, T and U decouple in the limit that the string scale $M_S$ goes to infinity. The oblique parameters constrain the lower limit on $M_S.$ Taking the quantum gravity cutoff to be $M_S,$ S-parameter constraints impose $M_S>1.55\mathrm{}$ TeV for $n=2\mathrm{}$ at the $1\sigma$ level. T-parameter constraints impose $M_S>1.25\mathrm{}$ (0.75) TeV for $n=3\mathrm{}$ (6).

• Received 22 May 2000

DOI:https://doi.org/10.1103/PhysRevD.62.125018