  We show how leptogenesis can occur at the TeV scale with neutrinos that
possess almost purely Dirac masses and negligible Majorana mass contributions
as a consequence of the small wavefunction overlap in a warped fifth dimension.
Lepton number violation at the Planck scale is introduced via a Majorana mass
term on the Planck brane. Such a Majorana mass operator leads to the small mass
splitting of otherwise degenerate Kaluza-Klein excited states on the TeV brane.
This tiny mass splitting can compensate for the small Yukawa couplings to give
a CP asymmetry large enough to produce the sufficient baryon asymmetry from the
decay of the nearly degenerate neutrino Kaluza-Klein states. In this way the
standard baryogenesis via leptogenesis scenario can naturally occur at the TeV
scale without the need for a high mass scale.
