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We analyze the recently released Fermi-LAT data on the sum of electrons and positrons. Compared to a conventional, pre-Fermi, background model, a surprising excess in the several hundred GeV range is found and here we analyze it in terms of…

High Energy Astrophysical Phenomena · Physics 2009-09-02 Lars Bergstrom , Joakim Edsjo , Gabrijela Zaharijas

The excess in the positron fraction reported by the PAMELA collaboration has been interpreted as due to annihilation or decay of dark matter in the Galaxy. More prosaically, it has been ascribed to direct production of positrons by nearby…

High Energy Astrophysical Phenomena · Physics 2009-09-02 Philipp Mertsch , Subir Sarkar

We present a numerical extension to the analytical propagation model introduced in Hein and Spanier (2008) to describe the leptonic population in the galactic disc. The model is used to derive a possible identification of the components…

High Energy Astrophysical Phenomena · Physics 2011-07-06 Alex Ivascenko , Felix Spanier

In light of recent observations of an anomalous excess of high-energy positrons and electrons by the PAMELA and Fermi LAT experiments, we investigate exotic cosmic-ray signatures in scenarios with unstable dark matter that decays with an…

High Energy Physics - Phenomenology · Physics 2015-05-14 David Tran

Studying the acceleration and propagation mechanisms of Galactic cosmic rays can provide information regarding astrophysical sources, the properties of our Galaxy, and possible exotic sources such as dark matter. To understand cosmic ray…

High Energy Astrophysical Phenomena · Physics 2012-05-23 Juan Wu

Recent measurements of cosmic ray leptons by PAMELA, ATIC, HESS and Fermi revealed interesting excesses. Many authors suggested particle Dark Matter (DM) annihilations could be at the origin of these effects. In this paper, we critically…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Pierre Brun

The excesses in the electron and positron spectra observed by many experiments, such as PAMELA and AMS-02, have sparked significant theoretical investigation. It is not easy to distinguish the two primary hypotheses dark matter…

High Energy Astrophysical Phenomena · Physics 2024-11-07 Xing-Jian Lv , Xiao-Jun Bi , Kun Fang , Peng-Fei Yin , Meng-Jie Zhao

The overabundance of high-energy cosmic positrons, observed by PAMELA and AMS-02, can be considered as the consequence of dark matter decays or annihilations. We show that recent FERMI/LAT measurements of the isotropic diffuse gamma-ray…

High Energy Astrophysical Phenomena · Physics 2016-07-11 Maxim Laletin

The recent observations of the positron fraction in cosmic rays by PAMELA indicate that the fraction of positrons to the total electronic component in cosmic rays initially decreases in the energy region 1-10 GeV and increases thereafter.…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-11 R. Cowsik , B. Burch

The observations of the total electronic component and the positron fraction in cosmic rays by the FERMI, HESS, ATIC, and PAMELA instruments are studied with analytical propagation models, both for a set of discrete sources and for a…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-15 R. Cowsik , B. Burch

We use multi-component decaying dark matter (DM) scenario to explain the possible cosmic ray excesses in the positron fraction recently confirmed by AMS-02 and the total $e^+ +e^-$ flux observed by Fermi-LAT. In the two-component DM models,…

High Energy Physics - Phenomenology · Physics 2014-12-01 Chao-Qiang Geng , Da Huang , Lu-Hsing Tsai

In a recent letter, the AMS collaboration reported the detailed and extensive data concerning the distribution in energy of electron and positron cosmic rays. A central result of the experimental work resides in the energy regime $30\ {\rm…

High Energy Physics - Phenomenology · Physics 2015-02-10 A. Widom , J. Swain , Y. N. Srivastava

The unprecedented quality of the data collected by the AMS-02 experiment onboard the International Space Station allowed us to address subtle questions concerning the origin and propagation of cosmic rays. Here we discuss the implications…

High Energy Astrophysical Phenomena · Physics 2019-06-05 Carmelo Evoli , Roberto Aloisio , Pasquale Blasi

Several cosmic ray experiments have measured excesses in electrons and positrons, relative to standard backgrounds, for energies from ~ 10 GeV - 1 TeV. These excesses could be due to new astrophysical sources, but an explanation in which…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Spencer Chang , Lisa Goodenough

The PAMELA collaboration recently released the $e^+$ absolute spectrum between 1 and 300 GeV in addition to the positron fraction and the $e^-$ spectrum previously measured in the same period. We use the newly developed three-dimensional…

High Energy Astrophysical Phenomena · Physics 2014-04-30 Daniele Gaggero , Dario Grasso , Luca Maccione , Giuseppe Di Bernardo , Carmelo Evoli

In the light of the latest measurements on the total $e^+ + e^-$ flux by CALET and DAMPE experiments, we revisit the multicomponent leptonically decaying dark matter (DM) explanations to the cosmic-ray electron/positron excesses observed…

High Energy Physics - Phenomenology · Physics 2020-09-22 Chao-Qiang Geng , Da Huang , Lu Yin

The precision measurements of the spectra of cosmic ray nuclei and leptons in recent years have revealed the existence of multiple features, such as the spectral break at $\sim 300$ GV rigidity seen by PAMELA and AMS-02 and more recently…

High Energy Astrophysical Phenomena · Physics 2022-01-05 Carmelo Evoli , Elena Amato , Pasquale Blasi , Roberto Aloisio

The cosmic-ray excess observed by PAMELA in the positron fraction and by FERMI and HESS in the electron + positron flux can be interpreted in terms of DM annihilations or decays into leptonic final states. Final states into tau's or 4mu…

High Energy Physics - Phenomenology · Physics 2010-02-24 Patrick Meade , Michele Papucci , Alessandro Strumia , Tomer Volansky

Motivated by the anomalous positron flux recently reported by the PAMELA collaboration, we study the cosmic-ray positron produced by the pair annihilation and the decay of superparticle dark matter. We calculate the cosmic-ray positron flux…

High Energy Physics - Phenomenology · Physics 2015-05-13 Koji Ishiwata , Shigeki Matsumoto , Takeo Moroi