Despite the remarkable success of the ΛCDM model of cosmology, several tensions have emerged in recent years.
The most well-known example is the 4-5σ discrepancy between the value of the Hubble constant H0 measured with the local distance ladder and the one inferred using the cosmic microwave background (CMB). Another longstanding anomaly is the 2-3σ mismatch between the weak gravitational lensing and CMB determinations of the amplitude of matter fluctuations on 8 Mpc/h scales, typically parameterized as S8 ≡σ8(Ωm/0.3)^0.5. In this seminar, I discuss how the aforementioned tensions could be giving us hints about the properties of the dark sector in the universe. In particular, I’ll argue that the H0 and S8 tensions can be respectively explained by a dark energy component in the early universe and a scenario of 2-body decaying dark matter.