Synchrotron Self-Compton Process for Constraining sub-GeV Dark Matter in Omega Centauri via SKA

Abstract: The search for the particle identity of dark matter (DM) continues to be a primary objective in modern physics. In this field, the sub-GeV mass range of DM detection remains a crucial yet challenging window. We investigate synchrotron self-Compton (SSC) emission from electrons and positrons produced by MeV-scale DM annihilation as a novel indirect detection channel. Focusing on the globular cluster Omega Centauri and the sensitivity of the Square Kilometre Array, we derive constraints on the annihilation cross section reaching $$\langleσv\rangle \sim 10<sup>{-30}\,\rm{cm}<sup>{3}\,\rm{s}<sup>{-1}$$ in the tens-of-MeV range. Furthermore, constraints could even reach below $$\langleσv\rangle \sim 10<sup>{-32}\,\rm{cm}<sup>{3}\,\rm{s}<sup>{-1}$$ for extreme parameter choices. Remarkably, even under deliberately conservative astrophysical assumptions, this channel outperforms existing indirect limits, establishing SSC emission as a robust probe of sub-GeV DM.