Speaker
Description
We present a study of spin-2 mediated scalar dark matter. As a blueprint, we work in a warped extra-dimensional model such that the mediator(s) are the massive spin-2 Kaluza-Klein (KK) modes of the 5D graviton. On top of Standard Model particles, we focus on dark matter annihilations into KK-gravitons. Due to the longitudinal modes of the massive gravitons, any truncation of the KK-tower leads to a tremendous growth of the amplitude at large center of mass energies $\sqrt{s}$, which heavily impacts any phenomenological analysis. For the first time, we include the full KK-tower in this dark matter production process and find that this growth is unphysical and cancels once the full field content of the extra-dimensional theory is taken into account. Interestingly, this implies that it is not possible to approximate the results obtained in the full theory with a reduced set of effective interactions once $\sqrt{s}$ is greater than the lightest massive graviton. This casts some doubt on the universal applicability of previous studies with spin-2 mediators within an EFT framework and prompts us to revisit the phenomenological allowed parameter space.
