2025/07/21 by Benjamin R. Safdi, Safdi, Benjamin R., Weishuang Linda Xu +1 · 1 voice · 5 citations
#hep-ph #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.48550/arxiv.2507.15934
We show that minimal, fermionic dark matter (DM) models in the n-dimensional representation of the weak force with zero hypercharge that make up 100% of the DM under the standard cosmological history are strongly excluded for n < 9. This includes the thermal wino, which we show is ruled out even allowing for DM core sizes up to ∼6.7 kpc with the preferred local DM density or ∼3.7 kpc in addition to the local DM density being half the preferred value, at less than 0.2 GeV/cm3. We reach these conclusions through dedicated searches with 14 years of Fermi gamma-ray data in the inner Galaxy between 30 GeV and 2 TeV for the continuum gamma-rays produced in the decays of unstable particles produced in DM annihilation and bound-state formation processes. We consider a variety of Milky Way DM profiles in our analyses, including those motivated by modern hydrodynamic cosmological simulations, and show that all the n < 9 minimal DM models are disfavored even under the most conservative assumptions for these density profiles. While wino, quintuplet (n=5), and n = 7 DM models are strongly disfavored by our analyses under the standard cosmology, we discuss how non-standard cosmological histories or DM sub-fractions could still allow for these particles to be realized in nature, with discovery opportunities at next-generation particle colliders and gamma-ray telescopes.