University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Thursday, April 16th 2015
12:15 pm:
Speaker: Francis-Yan Cyr-Racine (Caltech/JPL)
Subject: A Particle Physicist's Nightmare: What If Dark Matter is Truly Dark?

Despite being ubiquitous throughout the Universe, the fundamental physics governing dark matter remains a mystery. Current dark matter searches implicitly assume that dark matter couples at some level to ordinary baryonic matter via Standard Model interactions. However, it remains possible that dark matter interacts so weakly with ordinary matter that it will escape detection with current and near-future technology. This particle physicist's nightmare forces us to consider other possible probes of dark matter physics. For instance, the evolution of cosmological density fluctuations on small causal length scales in the early epochs of the Universe is a very sensitive probe of the fundamental physics of dark matter. Studying the astrophysical structures that resulted from the gravitational collapse of fluctuations on these small scales can thus yield important clues about physical processes that took place in the dark sector in the early Universe. Today, most of these structures are locked-in deep inside the potential wells of massive galaxies, making the study of their properties difficult. Fortunately, due to fortuitous alignments between high-redshift bright sources and us, some of these galaxies act as spectacular strong gravitational lenses, allowing us to probe their inner structures. In this talk, we present a new statistical analysis formalism to extract information about mass substructures inside lens galaxies and discuss what this can tell us about dark matter physics.

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