Gustavo Marques-Tavares (Maryland)

10:00am Wednesday March 13, 2024

SPartAcous: a new interacting dark sector model faces cosmological tensions

The remarkable precision of current cosmological measurements has opened the possibility of studying the properties of dark matter, as well as other dark sector particles that were produced in the early universe. With the increasing precision of these measurements, some tension between different datasets has arisen, potentially signaling the need to go beyond $\Lambda$CDM. The most significant of these tensions is the discrepancy between low and high redshift measurements of the current expansion rate, $H_0$. In addition, there is a less significant tension in the quantity $S_8$, which is related to the matter power spectrum at scales of approximately 8 Mpc. In this talk, I will present a new model, the Stepped Partially Acoustic Dark Matter (SPartAcous), in which the presence of interacting dark radiation and an interacting dark matter component can simultaneously address both of these tensions. I will also present the results of using this model to fit different combinations of cosmological data, showing the improvements it provides over $\Lambda$CDM.