Speaker
Description
Strongly interacting dark sectors with pseudo–Nambu–Goldstone bosons provide a versatile framework for sub-GeV dark matter. While the original SIMP paradigm emphasises number-changing processes as the origin of the relic abundance, the phenomenology of pionic dark matter is considerably richer. Depending on the spectrum and couplings, the relic density can WIMP-annihilations, semi-annihilations involving vector mesons and further processes like $\pi\pi\pi\to\pi\rho$. A consistent treatment therefore requires a framework that simultaneously captures pion dynamics, vector mesons, anomalous interactions, and portal effects.
We consider QCD-like dark sectors in which the dark matter candidates are pions. The effective theory is formulated using the Hidden Local Symmetry (HLS) approach, and is applicable to complex, real, and pseudo-real fermion theories.
As a minimal benchmark, we focus on the pseudo-real symmetry-breaking pattern $SU(4)/Sp(4)$.