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As the electromagnetic gauge symmetry makes the electron stable, a new abelian gauge symmetry may be responsible for the stability of superheavy dark matter. The gauge boson associated with the new gauge symmetry naturally plays the role of…

High Energy Physics - Phenomenology · Physics 2015-06-16 Jong-Chul Park , Seong Chan Park

The spectral characteristics of the pulsed gamma-ray emission from outer-magnetospheric particle accelerators are investigated. Either positrons or electrons are accelerated outwards by the magnetic-field-aligned electric field to emit…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Kouichi Hirotani

Recent measurements of the Geminga and B0656+14 pulsars by the gamma-ray telescope HAWC (along with earlier measurements by Milagro) indicate that these objects generate significant fluxes of very high-energy electrons. In this paper, we…

High Energy Astrophysical Phenomena · Physics 2017-11-22 Dan Hooper , Ilias Cholis , Tim Linden , Ke Fang

Recent EGRET observations of the diffuse Galactic gamma-ray emission reveal a spectrum which is incompatible with the assumption that the cosmic ray spectra measured locally hold throughout the Galaxy: the spectrum above 1 GeV, where the…

Astrophysics · Physics 2009-11-07 I. Büsching , M. Pohl , R. Schlickeiser

We review gamma-ray observations that constrain antimatter - both baryonic and leptonic - in the Universe. Antimatter can be probed through ordinary matter, with the resulting annihilation gamma-rays providing indirect evidence for its…

High Energy Astrophysical Phenomena · Physics 2014-01-29 Peter von Ballmoos

Dark matter annihilation in Galactic substructure produces diffuse gamma-ray emission of remarkably constant intensity across the sky, and in general this signal dominates over the smooth halo signal at angles greater than a few tens of…

High Energy Astrophysical Phenomena · Physics 2009-07-02 Jennifer M. Siegal-Gaskins

The galactic 511 keV gamma-ray line has been observed since 1970's, and was identified as the result of electron-positron annihilation, but the origin of such positrons is still not clear. Apart from the astrophysical explanations, the…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-19 Rong-Gen Cai , Yu-Chen Ding , Xing-Yu Yang , Yu-Feng Zhou

While the excess in cosmic-ray electrons and positrons reported by PAMELA and Fermi may be explained by dark matter decaying primarily into charged leptons, this does not necessarily mean that dark matter should not have any hadronic decay…

High Energy Physics - Phenomenology · Physics 2010-02-16 Chuan-Ren Chen , Sourav K. Mandal , Fuminobu Takahashi

We study cosmic-rays in decaying dark matter scenario, assuming that the dark matter is the lightest superparticle and it decays through a R-parity violating operator. We calculate the fluxes of cosmic-rays from the decay of the dark matter…

High Energy Physics - Phenomenology · Physics 2010-12-14 Koji Ishiwata , Shigeki Matsumoto , Takeo Moroi

Based on the Gluon Condensation (GC) model, the relationship between the spectra of electrons, $\gamma$ rays, and neutrinos in cosmic rays can be deduced. It has been found that these particles share the same parameter, $\beta_p$, and have…

High Energy Astrophysical Phenomena · Physics 2024-06-21 Jintao Wu , Jianhong Ruan

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

The spectral shape of the unresolved emission from different classes of gamma-ray emitters can be used to disentangle the contributions from these populations to the extragalactic gamma-ray background (EGRB). We present a calculation of the…

Astrophysics · Physics 2010-11-11 Vasiliki Pavlidou , Tonia M. Venters

The bulge of our Galaxy is illuminated by the 0.511 MeV gamma-ray line flux from annihilations of nonrelativistic positrons. The emission is strongly concentrated at the Galactic Center, in contrast to gamma-ray maps tracing nucleosynthesis…

Astrophysics · Physics 2008-11-26 Hasan Yuksel

Rare decays of light mesons may be a discovery window for a new weakly coupled forces hidden at low energy QCD scale. BES-III Collaboration reported the observation of the rare decay $\eta'\rightarrow\pi^0\gamma\gamma$. The observed decay…

High Energy Physics - Phenomenology · Physics 2019-11-27 Yaroslav Balytskyi

Secluded dark matter models, in which WIMPs annihilate first into metastable mediators, can present novel indirect detection signatures in the form of gamma rays and fluxes of charged particles arriving from directions correlated with the…

High Energy Physics - Phenomenology · Physics 2010-04-14 Brian Batell , Maxim Pospelov , Adam Ritz , Yanwen Shang

A sophisticated analysis of EGRET data has found evidence for gamma-ray emission from the galactic halo. I entertain the possibility that part of the EGRET signal is due to WIMP annihilations in the halo. I show that a viable candidate with…

Astrophysics · Physics 2007-05-23 Paolo Gondolo

Dark and baryonic matter contribute comparable energy density to the present Universe. The dark matter may also be responsible for the cosmic positron/electron excesses. We connect these phenomena with Dirac seesaw for neutrino masses. In…

High Energy Physics - Phenomenology · Physics 2009-10-29 Pei-Hong Gu , Utpal Sarkar , Xinmin Zhang

The Earth's high energy gamma-ray emission is caused by cosmic ray interactions with the atmosphere. The EGRET detector on-board the CGRO satellite is only the second experiment (after SAS-2) to provide a suitable dataset for the…

Astrophysics · Physics 2009-11-10 Dirk Petry

The annihilation of positrons in the Galaxy's interstellar medium produces characteristic gamma-rays with a line at 511 keV. This emission has been observed with the spectrometer SPI on INTEGRAL, confirming a puzzling morphology with bright…