Abstract:
It is quite conceivable that cosmology may give rise to appreciable populations of both particle dark matter and primordial black holes (PBH) with the combined mass density providing the observationally inferred value $\Omega_{DM}\approx 0.26$. However, previous studies have highlighted that scenarios with both particle dark matter and PBH are strongly excluded $\gamma$-ray limits assuming particle dark matter with a velocity independent thermal cross section $<\sigma v>~ 3\times10^{-26}{cm}^3/{s}$, as is the case for classic WIMP dark matter. Here we extend these existing studies on s-wave annihilating particle dark matter to ascertain the limits from diffuse gamma-rays on velocity dependent annihilations which are p-wave with $<\sigma v > ~ v^2$ or d-wave with $<\sigma v>~ v^4$. Furthermore, we highlight that even if the freeze-out process is p-wave it is relatively common for (loop/phase-space) suppressed s-wave processes to actually provide the leading contributions to the experimentally constrained gamma-ray flux from the PBH halo.