Migdal effect and photon Bremsstrahlung: improving the sensitivity to light dark matter of liquid argon experiments

Understand

The search for dark matter weakly interacting massive particles with noble liquids has probed masses down and below a GeV/c^2.

• The ultimate limit is represented by the experimental threshold on the energy transfer to the nuclear recoil.
• Currently, the experimental sensitivity has reached a threshold equivalent to a few ionization electrons.
• In these conditions, the contribution of a Bremsstrahlung photon or a so-called Migdal electron due to the sudden acceleration of a nucleus after a collision might be sizable.