Bounds on Dark Matter Annihilation Cross-sections from Inert Doublet Model in the context of 21 cm Cosmology of Dark Ages

Abstract

We study the fluctuations in the brightness temperature of 21-cm signal $\delta T_{21}$ at the dark ages ($z\sim 100$) with a dark matter candidate in Inter Doublet Model (IDM). We then explore the effects of different fractions of IDM dark matter on $\delta T_{21}$ signal. The IDM dark matter masses are chosen in few tens of GeV region as well as in the high mass region beyond 500 GeV. It has been observed that the $\delta T_{21}$ signal is more sensitive in the dark matter mass range of $70-80$ GeV. A lower bound on annihilation cross-section for this dark matter is also obtained analyzing the $\delta T_{21}$ signal. This is found to lie within the range $6.5\times 10^{-29}\mathrm{c}{\mathrm{m}}^3/sec\le ⟨\sigma \mathrm{v}⟩\le 4.88\times 10^{-26}\mathrm{c}{\mathrm{m}}^3/sec$ for the IDM dark matter mass range $10\mathrm{GeV}\le m_{\chi }\le 990\mathrm{GeV}$.

Comments: 13 pages, 9 figures, 1 table, comments and suggestions are welcome