Millicharged Cosmic Rays and Low Recoil Detectors

Understand

We consider the production of a "fast flux" of hypothetical millicharged particles (mCPs) in the interstellar medium (ISM).

• We consider two possible sources induced by cosmic rays: (a) $pp\rightarrow$(meson)$\rightarrow$(mCP) which adds to atmospheric production of mCPs, and (b) cosmic-ray up-scattering on a millicharged component of dark matter.
• We notice that the galactic magnetic fields retain mCPs for a long time, leading to an enhancement of the fast flux by many orders of magnitude.
• In both scenarios, we calculate the expected signal for direct dark matter detection aimed at electron recoil.