Dark Matter with Pseudoscalar-Mediated Interactions Explains the DAMA Signal and the Galactic Center Excess

Chiara Arina (1) , Eugenio del Nobile , Paolo Panci (1)

1 IAP - Institut d'Astrophysique de Paris

We study a Dirac dark matter particle interacting with ordinary matter via the exchange of a light pseudoscalar, and analyze its impact on both direct and indirect detection experiments. We show that this candidate can accommodate the long-standing DAMA modulated signal and yet be compatible with all exclusion limits at 9 9_S% C.L. This result holds for natural choices of the pseudoscalar-quark couplings (e.g., flavor universal), which give rise to a significant enhancement of the dark matter-proton coupling with respect to the coupling to neutrons. We also find that this candidate can accommodate the observed 1-3 GeV gamma-ray excess at the Galactic center and at the same time have the correct relic density today. The model could be tested with measurements of rare meson decays, flavor changing processes, and searches for axionlike particles with mass in the MeV range.

Keywords: 95.35.+d; 12.60.-i; 98.70.Rz; Dark matter; Models beyond the standard model; gamma-ray sources; gamma-ray bursts; High Energy Physics - Phenomenology; Astrophysics - Cosmology and Nongalactic Astrophysics

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]

Chiara Arina, Eugenio del Nobile, Paolo Panci. Dark Matter with Pseudoscalar-Mediated Interactions Explains the DAMA Signal and the Galactic Center Excess. Physical Review Letters, 2015, 114, ⟨10.1103/PhysRevLett.114.011301⟩. ⟨insu-03644776⟩