Constraints on the basic parameters of dark matter using the Planck data

Abstract

Dark Matter annihilation or decay can affect the anisotropy of the cosmic microwave background (CMB). Therefore, the CMB data can be used to constrain the properties of a dark matter particle. In this work, we use the new CMB data obtained by the Planck satellite to investigate the limits on the basic parameters of a dark matter particle. The parameters are the dark matter mass ($m_{\chi}$) and the thermally averaged cross section ($\langle\sigma v\rangle$) for dark matter annihilation and the decay rate ($\Gamma$) (or lifetime $\tau = 1/\Gamma$) for dark matter decay. For dark matter annihilation we also consider the impact of the structure formation process which is neglected by the recent work. We find that for DM annihilation, the constraints on the parameters are $f_{ann}=\langle \sigma v\rangle /m_{\chi}< 0.16 \times 10^{-26} \mathrm{cm^{3}s^{-1}GeV^{-1}}$(or $f_{ann}<0.89 \times 10^{-6} \mathrm{m^{3}s^{-1}kg^{-1}}$, $95\%$ C.L.). For DM decay, the constraints on the decay rate are $\Gamma < 0.28 \times 10^{-25} \mathrm{s^{-1}}$($95\%$ C.L.).