The Dark Dimension and its interplay with DESI data

by Georges Obied (Chicago U.)

Thursday 4 Dec 2025, 13:30 → 14:30 Europe/Zurich

4/2-037 - TH meeting room (CERN)

In this talk, I will discuss the motivation for considering an extra mesoscopic Dark Dimension of length l ~ 1 - 10 microns, taking into account theoretical and observational arguments. I will then talk about cosmological aspects of the Dark Dimension. In particular this scenario leads, by the universal coupling of the Standard Model sector to bulk gravitons, to massive spin 2 KK excitations of the graviton in the Dark Dimension (the “dark gravitons”) as an unavoidable dark matter candidate. Observations allow such an extra dimension of size in the micron range. Finally, I will discuss how this scenario can naturally accommodate features recently observed by the DESI survey such as an effective dark energy equation of state that is smaller than -1.