Searching for Boosted Dark Matter mediated by a new Gauge Boson

Abstract

We study the possibility to directly detect the boosted dark matter generated from the scatterings with high energetic cosmic particles such as protons and electrons. As a concrete example, we consider the sub-GeV dark matter mediated by a U (1)D gauge boson which has mixing with U (1)Y gauge boson in the standard model. The enhanced kinetic energy of the light dark matter from the collision with the cosmic rays can recoil the target nucleus and electron in the underground direct detection experiments transferring enough energy to them to be detectable. We show the impact of BDM with existing direct detection experiments as well as collider and beam-dump experiments.

Cosmic-Neutrino-Boosted Dark Matter ($ν$BDM)

“…This low kinetic energy causes a significant problem in detecting light dark matter since the recoil energy of scattered SM particle is also limited by the kinetic energy 1 . On the other hand, there still exists a chance to detect a subcomponent of DM, dubbed 'boosted dark matter' (BDM), which may carry much larger energy beyond threshold due to various mechanisms [4][5][6][7][8][9][10] including scattering by energetic cosmic-ray particles [11][12][13][14][15][16][17]. We note that focus has been given to cosmic-ray electron and proton so far even though the chance is not exclusively open for charged particles.…”

Elastic and Inelastic Scattering of Cosmic-Rays on Sub-GeV Dark Matter

“…In principle, both elastic scatterings and inelastic scatterings contribute to the accelerated DM flux. The scenario involving only the elastic scattering has been well studied in previous literature [1][2][3][4][5][6][7][8][9][10][12][13][14]. In this subsection we for the first time include the contributions from the inelastic channels and discuss their possible implications.…”

“…In addition to all these model-independent studies above, Refs. [7][8][9][10] explored the CR-boosted DM signals based on simple microscopic DM models and placed limits on the coupling constants and masses related to the dark sectors. Very recently, an excess of O(keV) electronic recoil events has been observed in XENON1T [11].…”

“…Besides, as we aim to cover a wide energy scales over several orders of magnitudes in this study, a consistent treatment based on a specific model taking fully into account the energy dependence as done in Ref. [7][8][9][10] is required. For illustration, we simply consider a fermionic DM which couples to baryons via a new dark vector boson.…”

Constraints on cosmic-ray boosted dark matter in CDEX-10 *

“…It is likely that DM is scattered and boosted by relativistic cosmic rays in the expanding universe. Several studies have already investigated CRBDM and offered relatively tight constraints on light DM, including the diurnal effect [41], DM-nucleon interactions propagated by various mediators [42][43][44][45] and the so-called reverse direct detection method [46]. There are cosmological constraints from Big Bang Nucleisynthesis (BBN) and the DM relic density.…”