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 $⟨\sigma v⟩\sim 10^{-29}{\mathrm{cm}}^3{\mathrm{s}}^{-1}$ in the tens-of-MeV range. Furthermore, constraints can reach below $⟨\sigma v⟩\sim 10^{-30}{\mathrm{cm}}^3{\mathrm{s}}^{-1}$ under favorable parameter choices. Although the derived limits depend on the uncertain propagation parameters, the SSC channel remains competitive with existing indirect constraints over a representative range of astrophysical assumptions, establishing SSC emission as a promising probe of sub-GeV DM.

6 pages, 3 figures