Directly Detecting Sub-GeV Dark Matter with Electrons from Nuclear Scattering

Area of Science:

• Particle Physics
• Cosmology
• Astrophysics

Background:

• Sub-GeV dark matter particles are theoretically compelling but challenging for direct detection.
• Traditional direct detection methods struggle with low-mass dark matter due to small recoil energies.
• Weakly interacting massive particles (WIMPs) are a common dark matter candidate, but sub-GeV alternatives are gaining traction.

Purpose of the Study:

• To explore a novel detection mechanism for sub-GeV dark matter.
• To assess the impact of electron ionization following dark matter-nucleus scattering on detection sensitivity.
• To evaluate the potential for existing and future experiments to probe dark matter properties.

Main Methods:

• Theoretical modeling of dark matter-nucleus scattering.
• Inclusion of atomic electron ionization as a detectable signal.
• Analysis of experimental sensitivity to sub-GeV dark matter cross-sections.

Main Results:

• Demonstrated that electron detection significantly enhances sensitivity to sub-GeV dark matter.
• Showed that even unobservable nuclear recoils can yield detectable electron signals.
• Established that current experiments already provide world-leading limits for this scenario.

Conclusions:

• The electron ionization channel is crucial for enhancing direct detection of sub-GeV dark matter.
• Future experiments utilizing this mechanism can probe dark matter cross-sections relevant to thermal freeze-out.
• This approach broadens the scope of direct detection experiments for light dark matter candidates.