Speaker
Description
Pseudo-Nambu-Goldstone boson (pNGB) dark matter is a compelling
scenario that naturally evades the increasingly stringent limits from
direct detection experiments. The elastic scattering cross-section
with nucleons is kinematically suppressed, allowing the model to
remain viable while achieving the correct thermal relic abundance.
However, the minimal pNGB realization suffers from a cosmological
domain wall problem caused by the spontaneous breaking of a discrete
symmetry. In this talk, we explore theoretical extensions designed to
resolve this issue. Specifically, we discuss models that embed the
symmetry into continuous gauge symmetries, such as U(1)_{B-L} or
U(1)_D, as well as frameworks introducing permutation symmetries among
multiple complex scalar fields. Finally, we will briefly discuss
possibilities within these frameworks, including semi-annihilating and
multi-component pNGB dark matter scenarios.