Stellar Analogs of Cosmic Dark-Sector Probes
Johns Hopkins University
I will talk about two new avenues for probing new light particles with stars, inspired by existing techniques in cosmology.
1. Spectral distortions of astrophysical blackbodies.
Recent studies reveal that more than a dozen of white dwarfs displaying near-perfect blackbody spectra in the optical range have been lurking in the SDSS catalog. In a way analogous to the cosmic microwave background, these stars serve as excellent testbeds for new physics. Specifically, I will show how the lack of distortions in the spectra of these stars translates into limits on axions.
2. Stellar Axion Background.
In order to maximize the discovery potential of new particles, it is useful to quantify their expected cosmic backgrounds from all possible sources and across all energy regimes. The aggregate of all the stars in the universe can source a cosmic population of keV-energy light particles, such as axions. These axions can subsequently decay into X-rays, which would stand out in the spectrum of the extragalactic background light, thereby allowing us to bound them.