scispace - formally typeset
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.

read more

Content maybe subject to copyright    Report

Citations
More filters
Journal ArticleDOI

A Systematic Effective Operator Analysis of Semi-Annihilating Dark Matter

TL;DR: In this paper, the authors use an effective operator approach to make the first model-independent study of the associated phenomenology of semi-annihilation and derive the irreducible constraints on models with single-component dark matter from cosmic ray searches and astrophysical observations.
Journal ArticleDOI

Antimatter in the universe and the PAMELA/FERMI/AMS anomaly

TL;DR: In this article, evidence for the existence of antimatter in the Galaxy and in the cosmos as a whole is reviewed and possible explanations that have been proposed for its origin discussed and discussed.
Journal ArticleDOI

State-selective high-energy excitation of nuclei by resonant positron annihilation

TL;DR: In this paper, the authors proposed a spectroscopic tool for an energy-selective excitation of nuclear transitions, which can efficiently populate nuclear levels of arbitrary multipolarities in the MeV regime.
Journal ArticleDOI

Probing the astrophysical origin of high-energy cosmic-ray electrons with Monte Carlo simulation

TL;DR: In this paper, the authors discuss the possible astrophysical origin of high-energy cosmic-ray electrons through a fully three-dimensional time-dependent Monte Carlo simulation, which provides valuable information on the electron-by-electron fluctuations, making it particularly suitable for analyzing in depth the single-source scenario.
Posted Content

Dark matter in a charged variant of the Scotogenic model

TL;DR: In this paper, a variant of the Scotogenic model that includes charged fermions and a doublet with hypercharge $3/2 was discussed, where neutrino masses are induced at the one-loop level thanks to the states belonging to the dark sector.
References
More filters
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.
Related Papers (5)

First result from the Alpha Magnetic Spectrometer on the International Space Station: precision measurement of the positron fraction in primary cosmic rays of 0.5-350 GeV.

M. Aguilar, +347 more

Measurement of Separate Cosmic-Ray Electron and Positron Spectra with the Fermi Large Area Telescope

Markus Ackermann, +158 more

Precision Measurement of the Proton Flux in Primary Cosmic Rays from Rigidity 1 GV to 1.8 TV with the Alpha Magnetic Spectrometer on the International Space Station

M. Aguilar, +294 more