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 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 Astroparticle Physics with H.E.S.S.: recents results and nearfuture prospects

2019 ◽  
Vol 209 ◽  
pp. 01054
Author(s):  
Emmanuel Moulin
Keyword(s):  
Dark Matter ◽  
Gamma Ray ◽  
Lorentz Invariance ◽  
Cosmic Ray ◽  
High Energy ◽  
New Physics ◽  
Galactic Centre ◽  
Astroparticle Physics ◽  
Dark Matter Search ◽  
Physics Program

H.E.S.S. is an array of five Imaging Atmospheric Cherenkov Telescopes located in Namibia. It is designed for observations of astrophysical sources emitting very-high-energy (VHE) gamma rays in the energy range from a few ten GeVs to several ten TeVs. The H.E.S.S. instrument consists of four identical 12 m diameter telescopes and a 28 m diameter telescope placed at the center of the array. An ambitious Astroparticle Physics program is being carried out by the H.E.S.S. collaboration searching for New Physics in the VHE gamma-ray sky. The program includes the search for WIMP dark matter and axion-like particles, tests of Lorentz invariance, cosmic-ray electron measurements, and search for intergalactic magnetic fields. I will present the latest results on dark matter search from the observations of the Galactic Centre region, the search for Lorentz invariance violation with the 2014 flare observation of Markarian 501, and the first measurement of the cosmic-ray electron spectrum up to 20 TeV. The future of the H.E.S.S. Astroparticle Physics program will be discussed.

scholarly journals Indirect searches for dark matter with the Fermi LAT instrument

2014 ◽  
Vol 29 (22) ◽  
pp. 1430030 ◽  
Author(s):  
M. N. Mazziotta ◽  
Keyword(s):  
Dark Matter ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Weakly Interacting Massive Particles ◽  
Current Status ◽  
Large Area ◽  
Weakly Interacting ◽  
Electron Positron ◽  
Massive Particles ◽  
Particle Dark Matter

In this review the current status of several searches for particle dark matter with the Fermi Large Area Telescope instrument is presented. In particular, the current limits on the weakly interacting massive particles, obtained from the analyses of gamma-ray and cosmic ray electron/positron data, will be illustrated.

scholarly journals New Physics of Strong Interaction and Dark Universe

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 196
Author(s):  
Vitaly Beylin ◽  
Maxim Khlopov ◽  
Vladimir Kuksa ◽  
Nikolay Volchanskiy
Keyword(s):  
Dark Matter ◽  
Cosmic Rays ◽  
Early Universe ◽  
Charged Particles ◽  
Cosmic Ray ◽  
High Energy ◽  
New Physics ◽  
Strong Interactions ◽  
History Of

The history of dark universe physics can be traced from processes in the very early universe to the modern dominance of dark matter and energy. Here, we review the possible nontrivial role of strong interactions in cosmological effects of new physics. In the case of ordinary QCD interaction, the existence of new stable colored particles such as new stable quarks leads to new exotic forms of matter, some of which can be candidates for dark matter. New QCD-like strong interactions lead to new stable composite candidates bound by QCD-like confinement. We put special emphasis on the effects of interaction between new stable hadrons and ordinary matter, formation of anomalous forms of cosmic rays and exotic forms of matter, like stable fractionally charged particles. The possible correlation of these effects with high energy neutrino and cosmic ray signatures opens the way to study new physics of strong interactions by its indirect multi-messenger astrophysical probes.

V-PARTICLE AGAIN?

2011 ◽  
Vol 20 (08) ◽  
pp. 1399-1412 ◽  
Author(s):  
SHOU-HUA ZHU
Keyword(s):  
Dark Matter ◽  
Cosmic Ray ◽  
Strange Particle ◽  
High Energy ◽  
Neutrino Telescope ◽  
Decay Length ◽  
Atmospheric Neutrinos ◽  
Numerical Estimation ◽  
Dark Sector ◽  
Electron Positron

This talk is mainly based on our previous work.1 We will investigate the possibility of detecting light long-lived particle (LLP) produced by high energy cosmic ray colliding with atmosphere. The LLP may penetrate the atmosphere and decay into a pair of muons near/in the neutrino telescope. Such muons can be treated as the detectable signal for neutrino telescope. The particle with such behavior is very similar with that of the first observed strange particle in cosmic ray events, which was coined historically as "V-particle" in some literature. This study is motivated by recent cosmic electron/positron observations which suggest the existence of O(TeV) dark matter and new light O(GeV) particle. It indicates that dark sector may be complicated, and there may exist more than one light particle, for example the dark gauge boson A′ and associated dark Higgs boson h′. In this work, we discuss the scenario with A′ heavier than h′ and h′ is treated as LLP. Based on our numerical estimation, we find that the large volume neutrino telescope IceCube has the capacity to observe several tens of di-muon events per year for favorable parameters if the decay length of LLP can be comparable with the depth of atmosphere. The challenge here is how to suppress the muon background induced by cosmic rays and atmospheric neutrinos.

scholarly journals The Cloudy Universe

1999 ◽  
Vol 16 (3) ◽  
pp. 262-272 ◽  
Author(s):  
Mark Walker ◽  
Mark Wardle
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Thermal Emission ◽  
Light Element ◽  
Cosmic Ray ◽  
Observational Constraints ◽  
X Ray ◽  
Hadron Phase ◽  
Planetary Mass ◽  
Hα Emission

AbstractModelling of extreme scattering events suggests that the Galaxy's dark matter is an undetected population of cold, AU-sized, planetary-mass gas clouds. None of the direct observational constraints on this picture—thermal/non-thermal emission, extinction and lensing—are problematic. The theoretical situation is less comfortable, but still satisfactory. Galactic clouds can survive in their current condition for billions of years, but we do not have a firm description for either their origin or their evolution to the present epoch. We hypothesise that the proto-clouds formed during the quark–hadron phase transition, thereby introducing the inhomogeneity necessary for compatibility with light element nucleosynthesis in a purely baryonic universe. We outline the prospects for directly detecting the inferred cloud population. The most promising signatures are cosmic-ray-induced Hα emission from clouds in the solar neighbourhood, optical and X-ray flashes arising from cloud–cloud collisions, ultraviolet extinction, and three varieties of lensing phenomena.

scholarly journals The SHiP experiment at CERN

2018 ◽  
Vol 182 ◽  
pp. 02016 ◽  
Author(s):  
Walter M. Bonivento
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Theoretical Models ◽  
Mass Range ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Beam Dump ◽  
Weakly Coupled ◽  
Physics Potential ◽  
The Standard Model

The discovery of the Higgs boson has fully confirmed the Standard Model of particles and fields. Nevertheless, there are still fundamental phenomena, like the existence of dark matter and the baryon asymmetry of the Universe, deserving an explanation that could come from the discovery of new particles. Searches for new physics with accelerators are performed at the LHC, looking for high massive particles coupled to matter with ordinary strength. A new experiment at CERN meant to search for very weakly coupled particles in the few GeV mass domain has been recently proposed. The existence of such particles, foreseen in different theoretical models beyond the Standard Model, is largely unexplored. A beam dump facility using high intensity 400 GeV protons is a copious source of such unknown particles in the GeV mass range. The beam dump is also a copious source of neutrinos and in particular it is an ideal source of tau neutrinos, the less known particle in the Standard Model. The neutrino detector can also search for dark matter through its scattering off the electrons. We report the physics potential of the SHiP experiment.

scholarly journals Neutrino experiments probe hadrophilic light dark matter

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Yohei Ema ◽  
Filippo Sala ◽  
Ryosuke Sato
Keyword(s):  
Dark Matter ◽  
Parameter Space ◽  
Large Volume ◽  
Direct Detection ◽  
Cosmic Ray ◽  
New Physics ◽  
Simplified Models ◽  
Large Volume Detector ◽  
Nuclear Recoils ◽  
Neutrino Experiments

We use Super-K data to place new strong limits on interactions of sub-GeV Dark Matter (DM) with nuclei, that rely on the DM flux inevitably induced by cosmic-ray upscatterings. We derive analogous sensitivities at Hyper-K and DUNE and compare them with others, e.g. at JUNO. Using simplified models, we find that our proposal tests genuinely new parameter space, allowed both by theoretical consistency and by other direct detection experiments, cosmology, meson decays and our recast of monojet. Our results thus motivate and shape a new physics case for any large volume detector sensitive to nuclear recoils.

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.

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