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The unexpected energy spectrum of the positron/electron ratio is interpreted astrophysically, with a possible exception of the 100-300 GeV range. The data indicate that this ratio, after a decline between $0.5-8$ GeV, rises steadily with a…

High Energy Astrophysical Phenomena · Physics 2016-10-11 M. A. Malkov , P. H. Diamond , R. Z. Sagdeev

Recent precision measurements of the flux of cosmic ray positrons by the Alpha Magnetic Spectrometer show that the spectrum has a marked softening feature for energies close to one TeV. A possible interpretation of this result is that the…

High Energy Astrophysical Phenomena · Physics 2019-02-19 Paolo Lipari

An new method of calculating the energy spectrum of neutrinos and antineutrinos produced in the electron-positron annihilation processes in hot stellar plasma is presented. Detection of these neutrinos, produced copiously in the…

Astrophysics · Physics 2007-05-23 M. Misiaszek , A. Odrzywolek , M. Kutschera

Cosmic ray antiprotons provide a powerful tool to probe dark matter annihilations in our galaxy. The sensitivity of this important channel is, however, diluted by sizable uncertainties in the secondary antiproton background. In this work,…

High Energy Physics - Phenomenology · Physics 2017-03-08 Martin Wolfgang Winkler

Dark Matter annihilation (DMA) may yield an excess of gamma rays and antimatter particles, like antiprotons and positrons, above the background from cosmic ray interactions. Several signatures, ranging from the positron excess, as observed…

Astrophysics · Physics 2009-11-13 W. de Boer

A number of signals involving charged cosmic rays and high-energy photons have been interpreted as being due to annihilating dark matter. This article provides an overview of the experimental evidence and discusses in particular detections…

Astrophysics · Physics 2007-05-23 U. Schwanke

We isolated the anomalous part of the cosmic electron-positron flux within a Bayesian likelihood analysis. Using 219 recent cosmic ray spectral data points, we inferred the values of selected cosmic ray propagation parameters. In the…

High Energy Astrophysical Phenomena · Physics 2012-04-25 Katie Auchettl , Csaba Balázs

We present a new measurement of the cosmic-ray positron fraction e+/(e+ + e-) obtained from the first balloon flight of the High Energy Antimatter Telescope (HEAT). Using a magnet spectrometer combined with a transition radiation detector,…

Astrophysics · Physics 2012-08-27 HEAT Collaboration

Pulsars are considered to be the leading explanation for the excess in cosmic-ray positrons detected by PAMELA and AMS-02. A notable feature of standard pulsar models is the sharp spectral cutoff produced by the increasingly efficient…

High Energy Astrophysical Phenomena · Physics 2023-05-24 Isabelle John , Tim Linden

The spectrum of positrons and antiprotons produced by the outflow of high temperature matter surrounding microscopic black holes is calculated for energies between five GeV and the Planck energy. The results may be applicable for the last…

Astrophysics · Physics 2009-11-11 R. G. Daghigh , J. I. Kapusta

Excitation of multicomponent dark matter in the galactic center has been proposed as the source of low-energy positrons that produce the excess 511 keV gamma rays that have been observed by INTEGRAL. Such models have also been promoted to…

High Energy Physics - Phenomenology · Physics 2010-05-28 James M. Cline

We present a scenario where dark matter is in the form of dark atoms that can accomodate the experimentally observed excess of positrons in PAMELA and AMS-02 while being compatible with the constraints imposed on the gamma-ray flux from…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Konstantin Belotsky , Maxim Khlopov , Chris Kouvaris , Maxim Laletin

The flux of cosmic ray antiprotons from neutralino annihilations in the galactic halo is computed for a large sample of models in the Minimal Supersymmetric extension of the Standard Model. We also revisit the problem of estimating the…

Astrophysics · Physics 2007-05-23 Lars Bergstrom , Joakim Edsjo , Piero Ullio

PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the…

High Energy Astrophysical Phenomena · Physics 2016-09-08 M. Casolino , The Pamela collaboration

A new calculation of the $\bar{p}/p$ ratio in cosmic rays is compared to the recent PAMELA data. The good match up to 100 GeV allows to set constraints on exotic contributions from thermal WIMP dark matter candidates. We derive stringent…

Astrophysics · Physics 2009-07-15 F. Donato , D. Maurin , P. Brun , T. Delahaye , P. Salati

Recently a cosmic ray propagation model has been introduced, where anisotropic diffusion is used as a mechanism to allow for $\mathcal{O}(100)$ km/s galactic winds. This model predicts a reduced antiproton background flux, suggesting an…

High Energy Astrophysical Phenomena · Physics 2010-12-06 Phillip Grajek , Kaoru Hagiwara

The AMS-02 collaboration has recently reported the antiproton to proton ratio with improved accuracy. In view of uncertainties of the production and the propagation of the cosmic rays, the observed ratio is still consistent with the…

High Energy Physics - Phenomenology · Physics 2015-06-24 Masahiro Ibe , Shigeki Matsumoto , Satoshi Shirai , Tsutomu T. Yanagida

The electron-positron annihilation source in the Galactic center region has recently been observed with INTEGRAL/SPI, which shows that this 511 keV source is strong and its extension is consistent with the Galactic bulge geometry. The…

Astrophysics · Physics 2007-05-23 S. Schanne , M. Casse , J. Paul , B. Cordier

After the PAMELA finding of an increasing positron fraction above 10 GeV, the experimental evidence for the presence of a new electron and positron spectral component in the cosmic ray zoo has been recently confirmed by Fermi-LAT. We show…

High Energy Astrophysical Phenomena · Physics 2017-08-23 Daniele Gaggero , Dario Grasso

We propose low-energy antideuterons in cosmic rays as a new possible signature for indirect detection of supersymmetric dark matter. Since the energy spectrum of the antiproton secondary component is still spoilt by considerable theoretical…

High Energy Physics - Phenomenology · Physics 2007-05-23 Fiorenza Donato