This study explores a two-component dark matter model in which one component,
heavier dark matter, annihilates into a lighter dark matter. The lighter dark
matter is expected to generate detectable signals in detectors due to its
enhanced momentum, enabling direct detection even for MeV-scale dark matter. We
investigate the effectiveness of directional direct detections, especially the
nuclear emulsion detector NEWSdm, in verifying these boosted dark matter
particles through nuclear recoil. In particular, we focus on light nuclei, such
as protons and carbon, as suitable targets for this detection method due to
their high sensitivity to MeV-scale dark matter. By modeling the interactions
mediated by a dark photon in a hidden U(1) gauge symmetry framework, we
calculate the expected dark matter flux and scattering rates for various
detector configurations. Our results show that nuclear emulsions have the
potential to yield distinct, direction-sensitive dark matter signals from the
Galactic center, providing a new way to probe low-mass dark matter parameter
spaces that evade conventional detection methods.
