202 research outputs found
Relic density of dark matter in brane world cosmology
We investigate the thermal relic density of the cold dark matter in the
context of the brane world cosmology. Since the expansion law in a high energy
regime is modified from the one in the standard cosmology, if the dark matter
decouples in such a high energy regime its relic number density is affected by
this modified expansion law. We derive analytic formulas for the number density
of the dark matter. It is found that the resultant relic density is
characterized by the ``transition temperature'' at which the modified expansion
law in the brane world cosmology is connecting with the standard one, and can
be considerably enhanced compared to that in the standard cosmology, if the
transition temperature is low enough.Comment: 8 pages, no figure, the version accepted for publication in
Phys.Rev.
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