Heavy Charged Leptons in 6-dimensional Randall-Sundrum Model
  We consider the effects of adding a fourth generation to a model with two compactified extra dimensions -- one warped and the other flat. The extra dimensions lead to towers of Kaluza-Klein (KK) Z bosons. Interestingly, the higher KK-Z modes depending on the flat dimension contribute more than the warped dimension.   These KK-Z modes enhance the cross-section of fourth generation charged leptons . The most promising signature is the heavy charged lepton decaying to a heavy neutrino and W boson. 
Erin De Pree, Dietrich Kiesewetter
hep-ph