We show that in a class of universal extra dimension models (UED), which
solves both the neutrino mass and proton decay problem, an admixture of KK
photon and KK right handed neutrinos can provide the required amount of cold
dark matter (CDM). This model has two parameters Rβ1 and MZβ²β (R is
the radius of the extra space dimensions and Zβ² the extra neutral gauge boson
of the model). Using the value of the relic CDM density, combined with the
results from the cryogenic searches for CDM, we obtain upper limits on Rβ1
of about 400-650 GeV and MZβ²ββ€1.5 TeV, both being accessible to LHC. In
some regions of the parameter space, the dark matter-nucleon scattering cross
section can be as high as of 10β44 cm2, which can be probed by the next
round of dark matter search experiments.Comment: 13 pages, 2 figures; minor changes; to appear in Phys. Rev.