  Sommerfeld enhancement and Breit-Wigner enhancement of the dark matter
annihilation have been proposed to explain the "boost factor" which is
suggested by observed cosmic ray excesses. Although these two scenarios can
provide almost indistinguishable effects on the cosmic ray fluxes, the cross
sections of the self-interaction in those enhancement mechanisms are
drastically different. As a result, we show that they can be distinguished by
examining the effects of the self-interaction on the halo shapes. In Sommerfeld
enhancement models with m_phi<100MeV and m_DM<3TeV, the self-interaction can
leave observable imprints in the galactic dynamics, while dark matter is
effectively collisionless in Breit-Wigner models.

High Energy Physics - Phenomenology