Search for Dark Matter Particle Interactions with Electron Final States with DarkSide-50

Area of Science:

• Particle Physics
• Astrophysics
• Cosmology

Background:

• Dark matter remains one of the most significant mysteries in physics.
• Understanding dark matter's nature requires exploring various interaction models and mass ranges.
• Direct detection experiments are crucial for probing dark matter candidates through their interactions with ordinary matter.

Purpose of the Study:

• To search for sub-GeV/c² dark matter particles interacting with electrons.
• To constrain new parameter space for dark matter-electron cross-section, axioelectric coupling, and dark photon kinetic mixing.
• To establish the first direct-detection constraints on sterile neutrino properties.

Main Methods:

• Utilized a low-radioactivity liquid argon exposure from the DarkSide-50 experiment.
• Analyzed ionization signals to detect potential dark matter interactions.
• Applied analysis techniques to exclude parameter space for specific dark matter models.

Main Results:

• Excluded new parameter space for the dark matter-electron cross section (σ[over ¯]_{e}).
• Set new limits on the axioelectric coupling constant (g_{Ae}) and dark photon kinetic mixing parameter (κ).
• Established the first direct-detection constraints on the mixing angle |U_{e4}|² for keV/c² sterile neutrinos.

Conclusions:

• The DarkSide-50 experiment provides stringent constraints on low-mass dark matter models involving electron interactions.
• This research expands the reach of direct detection experiments to new dark matter candidates and interaction channels.
• The findings contribute to a broader understanding of dark matter properties and the search for new physics beyond the Standard Model.