Direct dark matter searches via pseudo-scalar portal

We study a Dirac Dark Matter (DM) particle interacting with ordinary matter via a pseudo-scalar portal, and analyze its impact on direct detection experiments. This candidate can accommodate the long-standing DAMA modulated signal and yet be compatible with all exclusion limits at 99S% CL. This result holds for natural choices of the pseudo-scalar-quark couplings, and give rise to a significant enhancement of the DM-proton coupling with respect to the coupling to neutrons. The model could be tested with measurements of rare meson decays, flavor changing processes, and searches for axion-like particles with mass in the MeV range.