The cosmic-ray electron flux measured by the PAMELA experiment between 1 and 625 GeV

TL;DR

This paper presents precise measurements of cosmic-ray electrons from 1 to 625 GeV by PAMELA, revealing a smooth spectrum consistent with standard models and providing new insights into cosmic-ray origins and propagation.

Contribution

First measurement of cosmic-ray electrons above 50 GeV, extending the energy range and confirming a single power-law spectrum with no significant features.

Findings

Electron spectrum follows a power law with index -3.18 above 30 GeV.

No significant spectral features observed in the electron flux.

Results compatible with both standard diffusion models and models including new sources.

Abstract

Precision measurements of the electron component in the cosmic radiation provide important information about the origin and propagation of cosmic rays in the Galaxy. Here we present new results regarding negatively charged electrons between 1 and 625 GeV performed by the satellite-borne experiment PAMELA. This is the first time that cosmic-ray electrons have been identified above 50 GeV. The electron spectrum can be described with a single power law energy dependence with spectral index -3.18 +- 0.05 above the energy region influenced by the solar wind (> 30 GeV). No significant spectral features are observed and the data can be interpreted in terms of conventional diffusive propagation models. However, the data are also consistent with models including new cosmic-ray sources that could explain the rise in the positron fraction.