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14:00 Andrei Cuceu, University College London
Title: Cosmology with the Lyman-alpha forest
Abstract: The Lyman-alpha forest is the primary cosmological probe of the late Universe above redshift z>2. Baryon acoustic oscillation (BAO) measurements from the Lyman-alpha forest flux correlations have been used to study dark energy and dark matter, and in combination with other probes to constrain neutrino masses and the curvature of the Universe. I will present methods for measuring BAO from the Ly-alpha forest, and their cosmological implications. I will show how these measurements can help us constrain the Hubble constant without using cosmic microwave background anisotropies, and the implications for the Hubble tension. With the start of the Dark Energy Spectroscopic Instrument (DESI) survey next year, we are expecting about an order of magnitude more data compared to past surveys. This opens up new opportunities for extracting more cosmological information from the Ly-alpha forest through the Alcock-Paczynski test, and also for exploiting the synergies between Ly-alpha absorption and quasar clustering.
14:30 Patrick Fitzpatrick, MIT
Title: New Pathways to the Relic Abundance of Vector-Portal Dark Matter
Abstract: In the conventional weakly-interacting massive particle (WIMP) paradigm the late-time density of dark matter (DM) is set by the rate of two-body annihilations, but there has been considerable recent interest in exploring alternative DM scenarios where other interactions control the final abundance. I will show that by fully exploring the parameter space of a simple, weakly-coupled dark sector, we can find a rich set of novel pathways which lead to the observed relic density of DM. In particular, we can identify and characterize a general class of mechanisms in which the DM relic abundance is determined by processes controlling the thermal coupling of the DM and Standard Model (dubbed the KINetically DEcoupling Relic -- KINDER), generalizing previously-studied special cases of this behavior.