Constraining axion and ALP dark matter from misalignment during reheating
Yong Xu
Abstract
We explore the phenomenology of QCD axion and axionlike particle (ALP) dark matter production via misalignment during inflationary reheating. We investigate scenarios involving inflaton oscillating in a generic potential $\ensuremath{\sim}{\ensuremath{\phi}}^{n}$, considering inflaton decay and annihilation for reheating. For low reheating temperatures, the parameter space leading to the correct relic abundance can be enlarged beyond the standard case. Depending on the type of inflaton-matter couplings and the value of $n$, we find that certain parts of the extended parameter space are already constrained by ADMX, CAPP, and MUSE experiments. Future haloscope experiments are expected to impose more stringent constraints. We highlight the potential to utilize axion experiments in constraining the dynamics of reheating.