Speaker
Description
The QCD axion is a viable dark matter candidate as the misalignment mechanism can furnish the observed dark matter abundance. Although a wide range of axion decay constants $f_a$ are compatible with astrophysical bounds, very large $f_a \sim\mathcal{O}(10^{17}-10^{18}$) GeV (and small $f_a\sim \mathcal{O}(10^9-10^{10})$ GeV) values require a misalignment angle $\theta_\text{mis} \ll 1$ $(\pi - \theta_\text{mis} \ll 1$) which presents a fine-tuning problem. These decay constant values are within projected experimental sensitivity of planned and proposed experiments, which further motivates their investigation. I will present a new mechanism, called Dynamical Axion Misalignment Production (DAMP), wherein these misalignment angles arise naturally. In addition to the presenting criteria for a DAMP model I will discuss, as a proof of principle, a set of SUSY QCD models which exhibit DAMP. These models predict a precise value for $f_a$ and the absence of isocurvature perturbations.
