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Open AccessJournal ArticleDOI

Cosmic-Ray Positron Energy Spectrum Measured by PAMELA

TLDR
The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy.
Abstract
Precision measurements of the positron component in the cosmic radiation provide important information about the propagation of cosmic rays and the nature of particle sources in our Galaxy. The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy. The combined measurements of the cosmic-ray positron energy spectrum and fraction provide a unique tool to constrain interpretation models. During the recent solar minimum activity period from July 2006 to December 2009, approximately 24 500 positrons were observed. The results cannot be easily reconciled with purely secondary production, and additional sources of either astrophysical or exotic origin may be required.

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Citations
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Journal ArticleDOI

What can we learn from a sharply falling positron fraction

TL;DR: In this paper, the authors study the possibility that future data may show the positron fraction dropping down abruptly to the level expected with only secondary production, and forecast the implications of such a feature in terms of possible injection mechanisms that include both Dark Matter and pulsars.
Proceedings ArticleDOI

Cosmic rays observations and gamma rays

Paolo Lipari
TL;DR: In this article, a comparison of the spectra of different particle types is performed to understand the properties of the propagation of relativistic charged particles in the Galaxy. But the results are limited to the case of antiparticles (antiprotons and positrons).
References
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Journal ArticleDOI

Random Forests

TL;DR: Internal estimates monitor error, strength, and correlation and these are used to show the response to increasing the number of features used in the forest, and are also applicable to regression.
Journal ArticleDOI

Geant4—a simulation toolkit

S. Agostinelli, +126 more
TL;DR: The Gelfant 4 toolkit as discussed by the authors is a toolkit for simulating the passage of particles through matter, including a complete range of functionality including tracking, geometry, physics models and hits.
Journal ArticleDOI

Machine learning

TL;DR: Machine learning addresses many of the same research questions as the fields of statistics, data mining, and psychology, but with differences of emphasis.
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