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14:00 Keisuke Harigaya (Institute for Advanced Study)
Title: Axion Kinetic Misalignment and Axiogenesis
Abstract: We will introduce a new cosmological evolution of the QCD axion and an axion-like particle, where the axion field circulates in the potential. Axion dark matter is produced by kinetic misalignment, which allows for a decay constant much below the prediction of the conventional evolutions. The new axion dynamics creates the baryon asymmetry of the universe through axiogenesis. For the QCD axion, the electroweak phase transition temperature is required to be larger than that in the standard model and is predicted as a function of the axion decay constant. The mechanism provides a connection between electroweak scale physics and axion physics. For an axion-like particle, assuming the standard electroweak phase transition temperature, the coupling strength of the axion to standard model particles is predicted as a function of the axion mass.
14:30 Nikita Blinov (Fermilab)
Title: The (Really) Small Scale Structure of Dark Matter
Abstract: The statistical properties of dark matter (DM) on the largest scales in the universe are well described by the standard cosmological model. In contrast, comparatively little is known about the DM distribution within galaxies. I will discuss how early universe cosmological evolution and DM microphysics can result in enhanced structure, i.e. clumpiness, on sub-galactic scales. Using the examples of vector DM produced during inflation and a universe with a period of pre-nucleosynthesis matter domination, I will show how we can relate the microphysical parameters in these models (such as particle masses and lifetimes) to the late-time properties of gravitationally-bound DM clumps (such as their masses and sizes). Finally I will briefly mention the prospects for observing these objects.
