Speaker
Rajrupa Mondal
(University of Maryland College Park)
Description
A compelling production mechanism for QCD axion dark matter is from the scaling dynamics of early universe axion strings. We show that in DFSZ-like models containing tree-level interactions between fermions and the axion, friction between the thermal bath and the axion string drastically changes the behavior of the axion string network for lower $f_a$ values. Friction delays the onset of scaling and increases the energy density of axions. Once the effects of friction are included, we argue that in addition to the standard value of $m_a \sim$ meV, $m_a \sim 0.1$ eV also reproduces the dark matter energy density.
Authors
Anson Hook
(University of Maryland)
Rajrupa Mondal
(University of Maryland College Park)
Shourya Mukherjee