PAMELA/Fermi-LAT electron cosmic ray spectrum at ∼100 GeV: Implication for dark matter annihilation signal in accordance with the 130 GeV γ-ray line

Abstract

Recently, a tentative 130 GeV γ-ray line signal was identified by quite a few groups. If correct it would constitute a “smoking gun” for dark matter annihilations. Interestingly, the spectra of the cosmic ray electrons detected by PAMELA and Fermi-LAT both show tiny wiggle-like structure at ∼100 GeV, which might indicate a weak signal of the annihilation of ∼130 GeV dark matter particles into electrons/positrons with a velocity-weighted cross section 〈σv〉χχ→e+e−∼4×10−26 cm3s−1. The prospect of identifying such a potential weak dark-matter-annihilation electron and/or positron component by AMS-02, a mission to measure the high energy cosmic ray spectra with unprecedented accuracy, is investigated.