Constraints on Sub-GeV Dark-Matter-Electron Scattering from the DarkSide-50 Experiment.

Area of Science:

• Particle Physics
• Astrophysics
• Cosmology

Background:

• Dark matter remains a significant mystery in physics, with its nature and interactions yet to be fully understood.
• Direct detection experiments aim to identify dark matter particles through their interactions with ordinary matter.

Purpose of the Study:

• To establish new constraints on sub-GeV dark matter particles that scatter off electrons.
• To explore the potential of dual-phase argon time projection chambers for detecting low-energy electron recoils.

Main Methods:

• Analysis of 6780.0 kg d of data from the DarkSide-50 detector.
• Utilizing electroluminescence signals from ionized electrons extracted from a liquid argon target.
• Achieving a low analysis threshold of approximately 0.05 keVee, corresponding to three extracted electrons.

Main Results:

• New, stringent limits on dark matter-electron scattering for sub-GeV mass ranges (30-100 MeV/c²).
• Improvement upon existing limits from the XENON10 experiment for specific dark matter mass ranges.
• Demonstration of the DarkSide-50 detector's sensitivity to low-energy electron recoils.

Conclusions:

• The DarkSide-50 experiment provides valuable constraints on dark matter models involving light particles interacting with electrons.
• The high trigger efficiency and low energy threshold enable sensitive searches for low-mass dark matter.
• Further analysis with larger datasets can potentially uncover more about the properties of dark matter.