BSM PANDEMIC Delta Series: Pouya Asadi (MIT) and Huangyu Xiao (U. of Washington)

by Huangyu Xiao (University of Washington), Pouya Asadi (Massachusetts Institute of Technology)


Pouya Asadi: "A Next-To-Minimal Dark Matter Model"

The weak scale is universally accepted as the most well-motivated scale for thermal dark matter (DM) candidates. In this talk, I will discuss a very simple extension of minimal DM models with a new unstable relic that eventually decays to SM. I will analytically study the freeze out and the entropy injection in this setup with general freezeout interactions beyond the usual 2—>2 one. I will identify the viable mass and cross section ranges and also point out that the vast newly-opened parameter space could potentially be probed best by looking for early matter-dominant epochs.


Huangyu Xiao: "Axion Dark Matter in the Sky"

The axion, which was originally proposed to solve the strong CP problem, is also a viable dark matter candidate. If the initial axion field is not homogenized by inflation, it will imprint large isocurvature fluctuations at extremely small scales and form substructures with subplanetary masses. In recent years there have been proposals that appear capable of detecting substructures with such masses, opening the window to detect axions indirectly. In this talk, I will discuss the detectability of axion minihalos based on N-body simulations, focusing on the late-universe evolution. The present-day abundance and density profiles of axion minihalos in the Universe are obtained by extrapolating the simulation results analytically, suggesting that axion minihalos are detectable in future observations.