High Energy Physics Seminar

I will describe several searches for new physics using current and upcoming astrophysical measurements in the redshift range z=4-20. I will first describe the 21-cm line during the cosmic-dawn era and how to use it to search for dark matter (DM). The depth of the 21-cm signal acts as a thermostat that can be used to search for DM interactions with our sector, for instance through millicharges. I will illustrate how the timing of the 21-cm signal can also be used to tightly constrain the small-scale behavior of dark matter, and determine whether it's warm, fuzzy, or self interacting. I will then explain how the acoustic physics of recombination become imprinted onto the 21-cm fluctuations, providing a new standard ruler during cosmic dawn. This will bridge the gap in measurements of the expansion rate H(z) of our universe between the CMB and the local universe, which are presently at tension with each other. Finally, I will show how current HST measurements during reionization can be used to probe primordial non-Gaussianity at smaller scales than accessible by the CMB, providing a new window into the dynamics of inflation.

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