Experimental Seminars

Searching for the fundamental nature of dark matter in the cosmic large-scale structure

by Keir K. Rogers (University of Toronto)

Europe/Madrid
IFAE Seminar Room + Zoom (Hybrid Seminar)

IFAE Seminar Room + Zoom

Hybrid Seminar

https://us02web.zoom.us/j/89787514064?pwd=SkRaOElqanZRNFZXM2d2SE9PN1d0Zz09
Description

The fundamental nature of dark matter (DM) so far eludes direct detection experiments, but it has left its imprint in the large-scale structure (LSS) of the Universe. I will present a search using cosmic microwave background (CMB) and galaxy surveys for ultra-light DM particle candidates called axions that are well motivated from high energy theory. In combining these datasets, I will discuss how the presence of axions can improve consistency between these probes and, in particular, help alleviate the S_8 cosmological parameter tension (the discrepancy in the amplitude of density fluctuations as inferred from CMB and galaxy data). I will then present complementary searches for ultra-light and light (sub-GeV) DM using a LSS probe called the Lyman-alpha forest. By combining complementary large- and small-scale structure probes, I will demonstrate how current and forthcoming cosmological data will systematically test the nature of DM. In order to model novel DM physics accurately and efficiently in CMB and LSS probes, I will present new machine learning approaches using neural network "emulators" to accelerate DM parameter inference from days to seconds and active learning to reduce massively the computational expense.

Organized by

Carles Sánchez Alonso