A search for exotic dark matter (DM) in the sub-GeV mass range has been
conducted using 205 kgβ day data taken from a p-type point contact
germanium detector of CDEX-10 experiment at China Jinping underground
laboratory. New low-mass dark matter searching channels, neutral current
fermionic DM absorption (Ο+AβΞ½+A) and DM-nucleus
3β2 scattering (Ο+Ο+AβΟ+A), have been
analyzed with an energy threshold of 160 eVee. No significant signal was found.
Thus new limits on the DM-nucleon interaction cross section are set for both
models at sub-GeV DM mass region. A cross section limit for the fermionic DM
absorption is set to be 2.5Γ10β46cm2(90\% C.L.) at DM mass of
10 MeV/c2. For the DM-nucleus 3β2 scattering scenario, limits
are extended to DM mass of 5 MeV/c2 and 14 MeV/c2 for the massless dark
photon and bound DM final state, respectively.Comment: 5 pages, 7 figure