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Cosmic-ray electron flux measured by the PAMELA experiment between 1 and 625 GeV
O Adriani1, G C Barbarino, G A Bazilevskaya
1University of Florence, Department of Physics, I-50019 Sesto Fiorentino, Florence, Italy.
Physical Review Letters
|June 15, 2011
Summary
The PAMELA experiment measured cosmic ray electrons up to 625 GeV, identifying them above 50 GeV for the first time. The electron spectrum aligns with standard models but also supports theories of new cosmic ray sources.
Area of Science:
- Astrophysics
- Particle Physics
- Cosmic Ray Physics
Background:
- Cosmic rays provide insights into galactic origins and propagation.
- Understanding the electron component is crucial for astrophysical models.
Purpose of the Study:
- To present new measurements of the cosmic ray electron spectrum.
- To investigate electron behavior at high energies (1-625 GeV).
Main Methods:
- Utilized the satellite-borne PAMELA experiment.
- Analyzed data for negatively charged cosmic ray electrons.
Main Results:
- First identification of cosmic ray electrons above 50 GeV.
- Electron spectrum follows a power-law (index -3.18 ± 0.05) above 30 GeV.
- No significant spectral deviations observed, consistent with standard models.
Conclusions:
- Data supports conventional diffusive propagation models for cosmic rays.
- Findings are also compatible with models involving novel cosmic ray sources potentially explaining the positron fraction anomaly.
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