2016/11/21 by Yoshiaki Ishigure, Ishigure, Yoshiaki, M. Kakizaki +4
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #hep-ph
paper · pdf · doi:10.48550/arxiv.1611.06760
9 pages, 2 figures
arxiv created 2016/11/21 · openalex publication_date 2016/11/21 · arxiv updated 2016/11/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Universal extra dimension models with Kaluza-Klein parity provide us excellent candidates for dark matter. We consider phenomenological universal extra dimension models where the Kaluza-Klein (KK) mass spectrum is different from that of the minimal universal extra dimension model, and compute the thermal relic abundance of the first KK mode of the photon taking into account the production of second KK particles. It is pointed out that its thermal relic abundance depends significantly on the mass degeneracy between the KK-photon and other KK particles because of considerable coannihilation effects. The cosmologically favored compactification scale is shown to range from around 1 TeV to a few TeV even in the cases where one of the first KK particles is tightly degenerate with the first KK photon in mass.