Spectra of primary cosmic-ray positrons and electrons in the PAMELA experiment

Abstract

The PAMELA experiment is being conducted aboard the Russian satellite Resurs-DK 1, which was launched into a near-Earth circumpolar orbit on June 15, 2006. The instrument, which includes a magnetic spectrometer and an electromagnetic calorimeter (16X0), allows us to measure the fluxes of cosmic-ray electrons and positrons over a wide range of energies from ∼100 MeV to hundreds of GeV. This work presents the measurement data collected from July 2006 through January 2010 on the spectra of primary cosmic-ray electrons and positrons. At low energies, this spectrum is in good agreement with a diffusion model that includes reacceleration and damping. At high energies, the measured spectrum is harder than the one predicted.