# Cosmic-ray electron+positron spectrum from 7 GeV to 2 TeV with the Fermi Large Area Telescope

## TL;DR

This paper reports a detailed measurement of the cosmic-ray electron and positron spectrum from 7 GeV to 2 TeV using the Fermi Large Area Telescope, revealing a broken power law with a spectral break at 50 GeV and constraining the cutoff energy.

## Contribution

First precise measurement of the cosmic-ray electron+positron spectrum over this energy range with Fermi LAT, identifying spectral features and setting limits on the cutoff energy.

## Key findings

- Spectrum fits a broken power law with a break at 50 GeV.
- Above 50 GeV, the spectrum follows a single power law with index 3.07.
- Excludes an exponential cutoff below 1.8 TeV at 95% confidence level.

## Abstract

We present a measurement of the cosmic-ray electron+positron spectrum between 7 GeV and 2 TeV performed with almost seven years of data collected with the Fermi Large Area Telescope. We find that the spectrum is well fit by a broken power law with a break energy at about 50 GeV. Above 50 GeV, the spectrum is well described by a single power law with a spectral index of $3.07 \pm 0.02 \; (\text{stat+syst}) \pm 0.04 \; (\text{energy measurement})$. An exponential cutoff lower than 1.8 TeV is excluded at 95\% CL.