Results from PAMELA, ATIC and FERMI : Pulsars or Dark Matter ?

TL;DR

Recent satellite experiments have observed excesses in cosmic ray positrons and electrons, which could be explained by pulsars or dark matter annihilation, providing insights into the nature of dark matter.

Contribution

This paper reviews recent experimental results and discusses their implications for dark matter candidates and astrophysical sources like pulsars.

Findings

Positron excess detected by PAMELA at 10-100 GeV

Electron spectrum excess observed by ATIC, HESS, FERMI above 100 GeV

Possible explanations include pulsars or dark matter annihilation

Abstract

It is well known that the dark matter dominates the dynamics of galaxies and clusters of galaxies. Its constituents remain a mystery despite an assiduous search for them over the past three decades. Recent results from the satellite-based PAMELA experiment detect an excess in the positron fraction at energies between 10-100 GeV in the secondary cosmic ray spectrum. Other experiments namely ATIC, HESS and FERMI show an excess in the total electron (\ps + \el) spectrum for energies greater 100 GeV. These excesses in the positron fraction as well as the electron spectrum could arise in local astrophysical processes like pulsars, or can be attributed to the annihilation of the dark matter particles. The second possibility gives clues to the possible candidates for the dark matter in galaxies and other astrophysical systems. In this article, we give a report of these exciting developments.