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High Energy


QMAP Particles/Cosmology Seminar: Lingfeng Li

Description Speaker: Lingfeng Li
Title: New inflationary probes of axion dark matter
Room: 3024
Host: Da Liu
If a light axion is present during inflation and becomes part of dark matter afterwards, its quantum fluctuations contribute to dark matter isocurvature. In this article, we introduce a whole new suite of cosmological observables for axion isocurvature, which could help test the presence of axions, as well as its coupling to the inflaton and other heavy spectator fields during inflation such as the radial mode of the Peccei-Quinn field. They include correlated clock signals in the curvature and isocurvature spectra, and mixed cosmological-collider non-Gaussianities involving both curvature and isocurvature fluctuations with shapes and running unconstrained by the current data. Taking into account of the existing strong constraints on axion isocurvature fluctuations from the CMB, these novel signals could still be sizable and potentially observable. In some models, the signals, if observed, could even help us significantly narrow down the range of the inflationary Hubble scale, a crucial parameter difficult to be determined in general, independent of the tensor mode.
Date Mon, March 20, 2023
Time 1:30pm-3:00pm PDT
Duration 1 hour 30 minutes
Access Public
Created by High-Energy Seminars
Updated Tue, March 7, 2023 7:36pm PST
Send Reminder Yes  -  3 days 5 hour 0 minutes before start

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