Absolute electron and positron fluxes from PAMELA/Fermi and dark matter

Abstract

We extract the positron and electron fluxes in the energy range 10–100 GeV by combining the recent data from PAMELA and Fermi LAT. The absolute positron and electron fluxes thus obtained are found to obey the power laws: E−2.65 and E−3.06 respectively, which can be confirmed by the upcoming data from PAMELA. The positron flux appears to indicate an excess at energies E ≳ 50 GeV even if the uncertainty in the secondary positron flux is added to the Galactic positron background. This leaves enough motivation for considering new physics, such as annihilation or decay of dark matter, as the origin of positron excess in the cosmic rays.