Interpretations of the possible 42.7 GeV $\gamma$-ray line

Abstract

Recently Liang et al. found a tentative line signal at about 43 GeV in the directions of sixteen nearby Galaxy Clusters. If arising from dark matter annihilation, the mass of the dark matter particles should be $m_{\chi}\sim 43$ GeV and the annihilation cross section $\langle \sigma v \rangle \sim 5\times10^{-28}(\overline{\rm BF}/10^{3})^{-1}~{\rm cm^3~s^{-1}}$ is needed, where $\overline{\rm BF}$ is the averaged boost factor of the annihilation signal of these Galaxy Clusters. In this work we discuss several models which could interpret these features and estimate the model parameters. Usually sizeable coupling parameter is needed. The $2\sigma$ upper limits on the cross section of the dark matter annihilation into various final states such as $b\bar{b}$, $\mu^+\mu^-$ and so on are also presented.