APEC Seminar (Astronomy - Particle Physics - Experimental Physics - Cosmology)

Speaker: Hideki Tanimura (Kavli IPMU)
Title: Testing decay dark matter model with the Sunyaev Zel’dovich effect for the S8 tension
Date (JST): Thu, Jan 26, 2023, 11:00 - 12:00
Place: Hybrid
Abstract: As a possible solution for the S8 tension, we extended the standard LambdaCDM cosmological model by including decay of dark matter (DDM). We considered two DDM models: one that dark matter decays into a form of non-interacting dark radiation (DDM1) and the other that dark matter decays into warm dark matter and dark radiation (DDM2). We studied the impacts of these DDM models on the Sunyaev Zel'dovich effect, includingthe background evolution in cosmology and non-linear prescription in the halo mass function. Performing a cosmological analysis by combining the latest Planck CMB measurement and SZ measurements, our result shows a preference for a decay lifetime of ~ 200 Gyr in the DDM1 model. However, the CMB data donot prefer this model and the S8 tension still remains. Additionally, we tested the DDM2 model and this model supports a decay lifetime of ~ 204Gyr to resolve the S8 tension with a lower bound on the decay lifetime of ~ 47 Gyr at 95% confidence level.