Sun Heated MeV-scale Dark Matter and the XENON1T Electron Recoil Excess

Abstract

The XENON1T collaboration reported an excess of the low-energy electron recoil events between 1 and 7 keV. We propose to explain such an anomaly by the MeV-scale dark matter (DM) heated by the interior of the Sun due to the same DM-electron interaction as in the detector. The kinetic energies of heated DM particles can reach a few keV, and naturally account for the excess signals detected by XENON1T. The inferred DM-electron scattering cross-section is about 0.1 pb, which is consistent with current observations. This model does not rely on any special assumptions on DM models, which serves as a general explanation of the XENON1T anomaly via DM-electron interaction. The spectrum of the Sun-heated DM is typically soft comparing to other boosted DM, so the small recoil events are expected to be abundant in this scenario. Future direct detection experiments with lower thresholds can distinguish this scenario with other boosted DM models or solar axion models.

Boosted Dark Matter Interpretation of the XENON1T Excess

“…Finally, we highlight that our BDM signals enjoy a daily modulation. Such a unique feature can be used to distinguish the signal proposed here from various backgrounds, as well as many other new physics interpretations of this excess [22][23][24][25]. Furthermore, the phase and the amplitude of the modulation can be used to extract crucial information about the BDM, e.g.…”

Gravitational Production of Hidden Photon Dark Matter in Light of the XENON1T Excess

“…The excess may be interpreted as a contribution from the solar axion [1], but this interpretation is inconsistent with the stellar cooling constraint, in particular the observation of white dwarfs and red giants [2]. On the other hand, various connections of the XENON1T excess with particle physics models, constraints and implications have been investigated in [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Absorption of bosonic dark matter (DM) may also give similar signals [19,20].…”

Collider Constraints on a Dark Matter Interpretation of the XENON1T Excess

“…In addition to the above interpretations, the XENON1T excess can also be explained by a flux of fast moving dark matter [10][11][12][13][14] with velocity v ∼ 0.05−0.20 and mass m DM 1MeV -10 GeV. In order to explain the XENON1T excess in this scenario, the product of dark matter density (n DM ) times the dark matter electron scattering cross-section at a momentum exchange equal to an inverse Bohr's radius (σ e ) has to be of order 10 −44 − 10 −43 cm −1 [10].…”