Comment on "Probing the Dark Matter-Electron Interactions via Hydrogen-Atmosphere Pulsating White Dwarfs''

Abstract

In Phys. Rev. D 98, 103023 (2018), a novel scenario was proposed to probe the interactions between dark matter (DM) particles and electrons, via hydrogen-atmosphere pulsating white dwarfs (DAVs) in globular clusters. The estimation showed that the scenario could hopefully test the parameter space: $5 \mathrm{GeV} \le m_{\chi} \le 10^{4} \mathrm{GeV}$ and $\sigma_{\chi,e} \ge 10^{-40} \mathrm{cm}^{2}$, where $m_{\chi}$ is the DM particle's mass and $\sigma_{\chi,e}$ is the elastic scattering cross section between DM and electron. In this comment, we have determined the exact lower limit of the testable DM particle mass $\sim 1.38 - 1.58 \mathrm{GeV}$, which depends on $\sigma_{\chi,e}$. This gives us a credible lower limit of the testable DM particle mass in above scenario, and provide a clear upper limit of the DM particle mass which we should consider in future research.