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It has recently been argued that the PAMELA, ATIC and PPB-BETS data showing an anomalous excess of high-energy cosmic ray positrons and electrons might be explained by dark matter annihilating in the Galactic halo with a cross section…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-05 Francis-Yan Cyr-Racine , Stefano Profumo , Kris Sigurdson

Multiwavelength observations suggest that clusters are reservoirs of vast amounts relativistic electrons and positrons that are either injected into and accelerated directly in the intra-cluster medium, or produced as secondary pairs by…

High Energy Astrophysical Phenomena · Physics 2019-08-15 Stephan Zimmer , Jan Conrad , Anders Pinzke

Both the robust INTEGRAL 511 keV gamma-ray line and the recent tentative hint of the 135 GeV gamma-ray line from Fermi-LAT have similar signal morphologies, and may be produced from the same dark matter annihilation. Motivated by this…

High Energy Physics - Phenomenology · Physics 2015-06-12 Yang Bai , Meng Su , Yue Zhao

The flux of the diffuse gamma-ray background radiation (GBR) does not confirm that the excess in the flux of cosmic ray electrons between 300-800 GeV, which was measured locally with the ATIC instrument in balloon flights over Antartica, is…

High Energy Astrophysical Phenomena · Physics 2011-09-28 Shlomo Dado , Arnon Dar

The gamma-ray line from dark matter (DM) annihilation is too weak to observe, but its observation will uncover much information, e.g., the DM mass and an nomalously large annihilation rate $\sim0.1$ pb into di-photon. In this work, we…

High Energy Physics - Phenomenology · Physics 2012-06-29 Zhaofeng Kang , Tianjun Li , Jinmian Li , Yandong Liu

High energy particles are produced by the annihilation of dark matter particles in our galaxy. These are presently searched for using balloon-borne antiproton and positron detectors and large area, deep underground neutrino telescopes. Dark…

High Energy Physics - Phenomenology · Physics 2016-09-01 F. Halzen , J. E Jacobsen

Due to their higher concentrations and small internal velocities, Milky Way subhalos can be at least as important as the smooth halo in accounting for the GeV positron excess via dark matter annihilation. After showing how this can be…

High Energy Astrophysical Phenomena · Physics 2010-08-13 Matthew D. Kistler , Jennifer M. Siegal-Gaskins

Ultra-high energy cosmic rays (UHECRs) may originate from the decay of massive relic particles in the dark halo of the Galaxy, or they may be produced by supermassive black holes in the nuclei of nearby galaxies. The anisotropy in the…

Astrophysics · Physics 2011-02-16 Wyn Evans , Francesc Ferrer , Subir Sarkar

We investigate if the gamma ray halo, for which recent evidence has been found in EGRET data, can be explained by neutralino annihilations in a clumpy halo. We find that the measured excess gamma ray flux can be explained through a moderate…

Astrophysics · Physics 2009-10-30 L. Bergstrom , J. Edsjo , P. Ullio

Bursts from the very early universe may lead to a detectable signal via the production of positrons, whose annihilation gives an observable X-ray signal. Using the absorption parameters for the annihilation photons of 511 keV, it is found…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-13 L. Stodolsky , J. Silk

In this paper we calculate the antiproton production in the annihilation of tensor dark matter and explore the possibility that the excess of antiprotons in the range $E_{K}=10-20 ~GeV$ reported by several groups in the analysis of the…

High Energy Physics - Phenomenology · Physics 2024-03-01 H. Hernández-Arellano , M. Napsuciale , S. Rodríguez , R. Ramírez-Cruz

Dark matter particles could annihilate into light and metastable mediators subsequently decaying far away from where they are produced. In this scenario, the indirect signatures of dark matter are altered with respect to the conventional…

High Energy Physics - Phenomenology · Physics 2017-11-29 Xiaoyong Chu , Suchita Kulkarni , Pierre Salati

We argue that we may be able to sort out dark matter models in which electrons are generated through the annihilation and/or decay of dark matter, by using a fact that the initial energy spectrum is reflected in the cosmic-ray electron flux…

It has been proposed that during the formation of the first generation stars there might be a "dark star" phase in which the power of the star comes from dark matter annihilation. The adiabatic contraction process to form the dark star…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-20 Qiang Yuan , Bin Yue , Bing Zhang , Xuelei Chen

If dark matter annihilates into standard model particles with a cross-section which is velocity dependent, then Local Group dwarf galaxies will not be the best place to search for the resulting gamma ray emission. A greater flux would be…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-16 Andrija Kostić , Deaglan J. Bartlett , Harry Desmond

We perform a detailed study of the sensitivity to the anisotropies related to Dark Matter (DM) annihilation in the Isotropic Gamma-Ray Background (IGRB) as measured by the Fermi Large Area Telescope (Fermi-LAT). For the first time, we take…

High Energy Astrophysical Phenomena · Physics 2011-09-07 A. Cuoco , A. Sellerholm , J. Conrad , S. Hannestad

A number of papers attempt to explain the positron anomaly in cosmic rays, observed by PAMELA and AMS-02, in terms of dark matter (DM) decays or annihilations. However, the recent progress in cosmic gamma-ray studies challenges these…

High Energy Astrophysical Phenomena · Physics 2017-01-12 Konstantin Belotsky , Ruslan Budaev , Alexander Kirillov , Maxim Laletin

Recent experimental measurements of the time interval between detection of the two photons emitted in positron/electron annihilation have indicated that collapse of the spatial part of the photon's wavefunction, due to detection of the…

Quantum Physics · Physics 2009-11-07 Victor D. Irby

Although the annihilation of positrons towards the Galactic centre was established more than 50 years ago through the detection of a 511 keV $\gamma$-ray line, the origin of the positrons remains unknown. The $\gamma$-ray line should be…

High Energy Astrophysical Phenomena · Physics 2025-08-27 Jürgen Knödlseder , Karim Sabri , Pierre Jean , Peter von Ballmoos , Gerry Skinner , Werner Collmar

Annihilation of dark matter particles in cosmological halos (including a halo of the Milky Way) contributes to the diffuse gamma-ray background (DGRB). As this contribution will appear anisotropic in the sky, one can use the angular power…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-31 Shin'ichiro Ando , Eiichiro Komatsu