Sub-GeV dark matter in superfluid He-4: an effective theory approach

Area of Science:

• Particle Physics
• Condensed Matter Physics
• Cosmology

Background:

• Dark matter remains undetected, necessitating novel detection strategies.
• Superfluid Helium-4 possesses unique gapless excitations (phonons) interacting with potential dark matter candidates.

Purpose of the Study:

• Investigate the detectability of sub-GeV dark matter via interactions with superfluid Helium-4 phonons.
• Utilize effective field theory and symmetry principles to model dark matter-phonon interactions.

Main Methods:

• Employ an effective field theory framework to describe dark matter interactions.
• Calculate emission rates for one and two phonons.
• Analyze differential distributions for phonon excitations.

Main Results:

• Symmetry dictates the possible interactions between dark matter and superfluid phonons.
• Combined analysis of one- and two-phonon emission provides a substantial exclusion region for dark matter masses.
• The effective field theory is well-defined for softer phonon excitations.

Conclusions:

• The proposed method offers a viable approach for constraining sub-GeV dark matter models.
• The framework is extensible to various dark matter models and detection scenarios.
• This research enhances strategies for direct dark matter detection experiments.