scholarly journals Interpretation of the CALET Electron+Positron Spectrum concerning Dark Matter Signatures

2019 ◽  
Author(s):  
Holger Motz ◽  
Yoichi Asaoka ◽  
Saptashwa Bhattacharyya
Keyword(s):  
Dark Matter ◽  
Electron Positron ◽  
Positron Spectrum

scholarly journals An interpretation of the cosmic ray e+ + e− spectrum from 10GeV to 3TeV measured by CALET on the ISS

2019 ◽  
Vol 28 (02) ◽  
pp. 1950035 ◽  
Author(s):  
Saptashwa Bhattacharyya ◽  
Holger Motz ◽  
Yoichi Asaoka ◽  
Shoji Torii
Keyword(s):  
Dark Matter ◽  
Electron Flux ◽  
Simulated Data ◽  
Flux Measurement ◽  
Cosmic Ray ◽  
Electron Positron ◽  
Positron Spectrum ◽  
Extra Electron ◽  
Electron Positron Pair ◽  
Combined Measurements

A combined interpretation of the Calorimetric Electron Telescope (CALET) [Formula: see text] spectrum up to 3[Formula: see text]TeV and the AMS-02 positron spectrum up to 500[Formula: see text]GeV was performed and the results are discussed. To parametrize the background electron flux, we assume a smoothly broken power-law spectrum with an exponential cutoff for electrons and fit this parametrization to the measurements, with either a pulsar or 3-body decay of fermionic Dark Matter (DM) as the extra electron–positron pair source responsible for the positron excess. We found that depending on the parameters for the background, both DM decay and the pulsar model can explain the combined measurements. While the DM decay scenario is constrained by the Fermi-LAT [Formula: see text]-ray measurement, we show that 3-body decay of a 800[Formula: see text]GeV DM can be compatible with the [Formula: see text]-ray flux measurement. We discuss the capability of CALET to discern decaying DM models from a generic pulsar source scenario, based on simulated data for five years of data-taking.

scholarly journals Constraining the annihilation of dark matter via cosmic-ray positrons and electrons

2021 ◽  
Vol 2145 (1) ◽  
pp. 012007
Author(s):  
Suwitchaya Setthahirun ◽  
Maneenate Wechakama
Keyword(s):  
Dark Matter ◽  
Cosmic Rays ◽  
Observational Data ◽  
Cross Section ◽  
Source Function ◽  
Cosmic Ray ◽  
Electron Channel ◽  
Diffusion Loss ◽  
Electron Positron ◽  
Positron Spectrum

Abstract We aim to constrain the properties of dark matter particles by several measurements of positrons and electrons from cosmic-rays. We assume that collisions of dark matter particles and dark matter anti-particles can produce positrons and electrons. The electron-positron propagation is explained by a diffusion-loss equation including loss rates, diffusion, as well as source function. We use data of cosmic-ray positrons and electrons detected by PAMELA, H.E.S.S., AMS-02 and Fermi-LAT. We compare the observational data with the electron and positron spectrum from five annihilation channels in our model to derive constraining factors regarding the cross-section of the annihilation of dark matter. The tightest constraint is provided by cosmic-ray positrons of AMS-02 for the electron channel. Dark matter with mass below a few GeV gets excluded by the cosmic-ray positrons of AMS-02 for the electron, muon and tau channels.

scholarly journals Formation of Elements and Compounds in Space in Early Universe

2016 ◽  
Vol 8 (6) ◽  
pp. 86
Author(s):  
Abdul L. Bhuiyan
Keyword(s):  
Dark Matter ◽  
High Temperature ◽  
Early Universe ◽  
High Speed ◽  
Virtual State ◽  
Speed Of Light ◽  
Electron Positron ◽  
Living Organisms ◽  
The Universe

<p class="1Body">At the end of the period of contraction of the universe, all objects transform into gravity particles such as photons and electron- positron pairs which exist in virtual state in spacetime at an extremely high temperature. These particles move with extremely high speed comparable to the speed of light. As the early universe starts cooling, the speed of the particles starts to decrease when photons and electron- positron pairs move out of spacetime and appear as real particles. As the temperature continues to fall due to cooling, the electron- positron pairs start forming quarks (u and d) while simultaneously the energy of photons transform into dark matter. The u quarks and d quarks then continue to form nuclei of different elements including radio elements. Simultaneously, the lighter elements such as hydrogen, nitrogen, carbon, oxygen, phosphorus, etc. form the precursors to DNAs and RNAs of living organisms.</p>

scholarly journals Indirect effects of dark matter

2019 ◽  
Vol 28 (13) ◽  
pp. 1941011 ◽  
Author(s):  
K. M. Belotsky ◽  
E. A. Esipova ◽  
A. Kh. Kamaletdinov ◽  
E. S. Shlepkina ◽  
M. L. Solovyov
Keyword(s):  
Dark Matter ◽  
Indirect Effects ◽  
Large Scale ◽  
Gamma Ray ◽  
Space Distribution ◽  
Stable Form ◽  
Final State ◽  
Electron Positron ◽  
Text Mode ◽  
The Universe

Here, we briefly review possible indirect effects of dark matter (DM) of the universe. It includes effects in cosmic rays (CR): first of all, the positron excess at [Formula: see text]500[Formula: see text]GeV and possible electron–positron excess at 1–1.5[Formula: see text]TeV. We tell that the main and least model-dependent constraint on such possible interpretation of CR effects goes from gamma-ray background. Even ordinary [Formula: see text] mode of DM decay or annihilation produces prompt photons (FSR) so much that it leads to contradiction with data on cosmic gamma-rays. We present our attempts to possibly avoid gamma-ray constraint. They concern with peculiarities of both space distribution of DM and their physics. The latter involves complications of decay/annihilation modes of DM, modifications of Lagrangian of DM-ordinary matter interaction and inclusion of mode with identical fermions in final state. In this way, no possibilities to suppress were found except, possibly, the mode with identical fermions. While the case of spatial distribution variation allows achieving consistency between different data. Also, we consider stable form of DM which can interact with baryons. We show which constraint such DM candidate can get from the damping effect in plasma during large-scale structure (LSS) formation in comparison with other existing constraints.

scholarly journals R-violating decay of Wino dark matter and electron/positron excesses in the PAMELA/Fermi experiments

2009 ◽  
Vol 680 (5) ◽  
pp. 485-488 ◽  
Author(s):  
Satoshi Shirai ◽  
Fuminobu Takahashi ◽  
T.T. Yanagida
Keyword(s):  
Dark Matter ◽  
Electron Positron

scholarly journals ELECTRON/POSITRON EXCESSES IN THE COSMIC RAY SPECTRUM AND POSSIBLE INTERPRETATIONS

2010 ◽  
Vol 19 (13) ◽  
pp. 2011-2058 ◽  
Author(s):  
YI-ZHONG FAN ◽  
BING ZHANG ◽  
JIN CHANG
Keyword(s):  
Dark Matter ◽  
Supernova Remnant ◽  
Cosmic Ray ◽  
Theoretical Models ◽  
New Physics ◽  
Observational Constraints ◽  
Correct Interpretation ◽  
Observational Feature ◽  
Electron Positron ◽  
Observational Status

The data collected by ATIC, PPB-BETS, FERMI-LAT and HESS all indicate that there is an electron/positron excess in the cosmic ray energy spectrum above ~100 GeV, although different instrumental teams do not agree on the detailed spectral shape. PAMELA also reported clearly the excessive feature of the fraction of positron above several GeV, but with no excess in antiprotons. Here we review the observational status and theoretical models of this interesting observational feature. We pay special attention to various physical interpretations proposed in the literature, including modified supernova remnant models for the e± background, new astrophysical sources, and new physics (the dark matter models). We suggest that although most models can make a case to interpret the data, with the current observational constraints the dark matter interpretations, especially those invoking annihilation, require much more exotic assumptions than some other astrophysical interpretations. Future observations may present some "smoking-gun" observational tests to differentiate different models and to identify the correct interpretation of the phenomenon.

scholarly journals Supersymmetric dark matter and the energy of a linear electron-positron collider

2000 ◽  
Vol 474 (3-4) ◽  
pp. 314-322 ◽  
Author(s):  
John Ellis ◽  
Gerardo Ganis ◽  
Keith A. Olive
Keyword(s):  
Dark Matter ◽  
Linear Electron ◽  
Electron Positron
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