The abundance of Kaluza-Klein dark matter with coannihilation

Fiona Burnell, Graham D. Kribs

Research output: Contribution to journalArticlepeer-review

128 Scopus citations


In universal extra dimension models, the lightest Kaluza-Klein (KK) particle is generically the first KK excitation of the photon and can be stable, serving as particle dark matter. We calculate the thermal relic abundance of the KK photon for a general mass spectrum of KK excitations including full coannihilation effects with all (level-one) KK excitations. We find that including coannihilation can significantly change the relic abundance when the coannihilating particles are within about 20% of the mass of the KK photon. Matching the relic abundance with cosmological data, we find the mass range of the KK photon is much wider than previously found, up to about 2 TeV if the masses of the strongly interacting level-one KK particles are within 5% of the mass of the KK photon. We also find cases where several coannihilation channels compete (constructively and destructively) with one another. The lower bound on the KK photon mass, about 540GeV when just right-handed KK leptons coannihilate with the KK photon, relaxes upward by several hundred GeV when coannihilation with electroweak KK gauge bosons of the same mass is included.

Original languageEnglish (US)
Article number015001
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number1
StatePublished - Jan 1 2006


Dive into the research topics of 'The abundance of Kaluza-Klein dark matter with coannihilation'. Together they form a unique fingerprint.

Cite this