High Energy Positrons and the WMAP Haze from Exciting Dark Matter

Understand

We consider the signals of positrons and electrons from "exciting" dark matter (XDM) annihilation.

• Because of the light (m_phi ~< 1 GeV) force carrier phi into which the dark matter states can annihilate, the electrons and positrons are generally very boosted, yielding a hard spectrum, in addition to the low energy positrons needed for INTEGRAL observations of the galactic center.
• We consider the relevance of this scenario for HEAT, PAMELA and the WMAP &#34;haze,&#34; focusing on light (m_phi ~< 2 m_pi) phi bosons, and find that significant signals can be found for all three, although significant signals generally require high dark matter densities.
• We find that measurements of the positron fraction are generally insensitive to the halo model, but do suffer significant astrophysical uncertainties.