Tracking Quintessence, WIMP Relic Density, PAMELA and Fermi LAT

Abstract

The generation of an early kination dominated era within a tracking quintessential model is investigated, the relic density of the Weakly Interacting Massive Particles (WIMPs) is calculated and we show that it can be enhanced with respect to its value in the standard cosmology. By adjusting the parameters of the quintessential scenario, the cold dark matter abundance in the universe can become compatible with large values for the annihilation cross section times the velocity of the WIMPs. Using these values and assuming that the WIMPs annihilate predominantly to $\mu^+\mu^-$, we calculate the induced fluxes of $e^\pm$ cosmic rays and fit the current PAMELA and Fermi-LAT data. We achieve rather good fits in conjunction with a marginal fulfillment of the restriction arisen from the cosmic microwave background radiation.