Light Thermal Dark Matter Beyond p-Wave Annihilation in Minimal Higgs Portal Model

This study explores a minimal renormalizable dark matter (DM) model, incorporating a sub-GeV Majorana DM and a singlet scalar particle. Using scalar and pseudo-scalar interactions (couplings cₛ and cₚ), we investigate implications for DM detection, considering s-wave, p-wave, and combined (s+p wave) contributions in DM annihilation cross-section, as well as loop-correction contributions to DM-nucleon elastic scattering. Identifying a broad parameter space (10 \, MeV 1\, GeV; (iii) the preferred -resonance region can be tested in the future indirect detection experiments, such as e-ASTROGAM.