Beyond the Standard Model through the Axion Lens

Speaker: Prateek Agrawal (Oxford)

Title: Beyond the Standard Model through the Axion Lens

Abstract: As the Standard Models of particle physics and cosmology have crystallized, foundational questions about the nature of the universe at the largest and smallest scales have come into sharper relief. I will give a broad overview of my research in the context of these questions, before focusing on a salient example: the axion. Axions are compelling candidates for new physics, providing a potential resolution to the strong-CP problem and an excellent dark matter candidate, and appearing ubiquitously in our best-understood theories of quantum gravity. They offer a rich tapestry of signals from cosmology, astrophysics to table-top experiments. The discovery of an axion will not just be a discovery of an extra particle: it can tell us about deep properties of the Standard Model, such as whether the fundamental forces unify, and what the fundamental quantum of electric charge is. I will present a striking cosmological signal that can give us access to these foundational questions. The signal is a polarization rotation of CMB light by an angle quantized in units of the fine structure constant. The current sensitivity of CMB experiments to this signal is 1%, with some tentative hints in the data and orders of magnitude improvement expected from the next generation cosmological experiments. Extracting the quantized signal will involve new analysis strategies for future CMB data.

ZOOM LINK:

https://ucsb.zoom.us/j/84217234934?pwd=Nk4ya1NLaWVMUVJLMEllcHJzQmRkdz09

Meeting ID: 842 1723 4934