Deciphering the Electron Spectral Hardening in AMS-02

TL;DR

This paper confirms a significant intrinsic spectral hardening in the primary electron component of cosmic rays around 42 GeV, likely due to interstellar transport or acceleration effects, using AMS-02 data.

Contribution

It introduces a new, realistic parametric fit for the electron spectrum and demonstrates the intrinsic nature of the spectral hardening with high significance.

Findings

Spectral hardening is intrinsic to primary electrons.

Significance of the feature is about 7 sigma.

Proposes interstellar effects as the likely cause.

Abstract

We analyze the electron cosmic-ray spectrum from AMS-02, focusing on the spectral hardening around 42 GeV. Our findings confirm that this feature is intrinsic to the primary electron component rather than a byproduct of contamination from primary positron sources. Even under conservative assumptions, its significance remains at about $7\sigma$, strongly indicating a genuine spectral break. Accordingly, we introduce a new, more realistic parametric fit, which we recommend for the next round of AMS-02 analyses. Once the sources of systematic uncertainties are better constrained, this refined approach can either reinforce or refute our conclusions, providing a clearer understanding of the observed electron spectrum. If confirmed, we propose that this hardening most likely arises from interstellar transport or acceleration effects.