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We extend the Standard Model by adding two gauge-singlet $\mathbb{Z}_{2}$% -symmetric scalar fields that interact with visible matter only through the Higgs particle. One is a stable dark matter WIMP, and the other one undergoes a…

High Energy Physics - Phenomenology · Physics 2011-06-07 Abdessamad Abada , Salah Nasri , Djamal Ghaffor

If Dark Matter (DM) is composed by Weakly Interacting Massive Particles, its annihilation in the halos harboring the earliest star formation episode may strongly influence the first generation of stars (Population III). Whereas DM…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-24 Fabio Iocco

Weakly Interacting Massive Particle (WIMP) direct detection experiments are closing in on the region of parameter space where neutralinos may constitute the Galactic halo dark matter. Numerical simulations and observations of galaxy halos…

Astrophysics · Physics 2017-08-23 Anne M Green

In the mixed dark matter scenarios consisting of primordial black holes (PBHs) and weakly interacting massive particles (WIMPs), WIMPs can be accreted onto PBHs to form ultracompact minihalos (UCMHs) with a density spike in the early…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-01 Yupeng Yang

The paradigm of the neutralino dark matter predicts that the first gravitationally bound objects are earth-mass sized microhaloes, which would emit annihilation gamma-rays. Here we show that, though the flux from individual nearest…

Astrophysics · Physics 2009-11-10 Takeshi Oda , Tomonori Totani , Masahiro Nagashima

Weakly interacting massive particles (WIMPs) remain the strongest candidates for the dark matter in the Universe. If WIMPs are the dark matter, they will form galactic halos according to the hierarchical clustering observed in N-body…

Astrophysics · Physics 2007-05-23 Angela V. Olinto , Pasquale Blasi , Craig Tyler

We consider possible mechanisms via which electroweak scale WIMPs \chi^0 could provide the source of the INTEGRAL/SPI 511 keV photon flux from the galactic centre. We consider scenarios where the WIMP spectrum contains near-degeneracies,…

High Energy Physics - Phenomenology · Physics 2009-11-13 Maxim Pospelov , Adam Ritz

We study the annihilating dark matter contribution to the extra-galactic diffuse gamma-ray background spectrum, motivated by the recent observations of cosmic-ray positron/electron anomalies. The observed diffuse gamma-ray flux provides…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-02 Masahiro Kawasaki , Kazunori Kohri , Kazunori Nakayama

The spectrum of photons arising from WIMP annihilation carries a detailed imprint of the structure of the dark sector. In particular, loop-level annihilations into a photon and another boson can in principle lead to a series of lines (a…

High Energy Astrophysical Phenomena · Physics 2009-09-02 Gianfranco Bertone , C. B. Jackson , Gabe Shaughnessy , Tim M. P. Tait , Alberto Vallinotto

Dark matter constitutes one of the most intriguing but so far unresolved issues in physics today. In many extensions of the Standard Model the existence of a stable Weakly Interacting Massive Particle (WIMP) is predicted. The WIMP is an…

Astrophysics · Physics 2019-08-13 Tomi Ylinen , Yvonne Edmonds , Elliott D. Bloom , Jan Conrad

Photons produced in the annihilations of dark matter particles can be detected by gamma-ray telescopes; this technique of indirect detection serves as a cornerstone of the upcoming assault on the dark matter paradigm. The main obstacle to…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-08 Eric J. Baxter , Scott Dodelson

We propose a new thermal freeze-out mechanism for ultra-heavy dark matter. Dark matter coannihilates with a lighter unstable species, leading to an annihilation rate that is exponentially enhanced relative to standard WIMPs. This scenario…

High Energy Physics - Phenomenology · Physics 2017-09-27 Asher Berlin

The Large Magellanic Cloud, at only 50 kpc away from us and known to be dark matter dominated, is clearly an interesting place where to search for dark matter annihilation signals. In this paper, we estimate the synchrotron emission due to…

High Energy Astrophysical Phenomena · Physics 2011-03-16 Beatriz B. Siffert , Angelo Limone , Enrico Borriello , Giuseppe Longo , Gennaro Miele

The annihilation of light dark matter was recently advocated as a possible explanation of the large positron injection rate at the Galactic center deduced from observations by the SPI spectrometer aboard INTEGRAL. The modelling of internal…

Astrophysics · Physics 2008-11-26 P. Sizun , M. Casse , S. Schanne

High-energy photons from dark matter annihilation contribute to the cosmic gamma-ray background (CGB). Since dark matter particles are weakly interacting, annihilation can happen only in high density regions such as dark matter halos. The…

Astrophysics · Physics 2007-05-23 Shin'ichiro Ando , Eiichiro Komatsu

We study the evolution of the first stars in the universe (Population III) from the early pre-Main Sequence until the end of helium burning in the presence of WIMP dark matter annihilation inside the stellar structure. The two different…

Astrophysics · Physics 2009-11-13 F. Iocco , A. Bressan , E. Ripamonti , R. Schneider , A. Ferrara , P. Marigo

An excess in gamma-rays emanating from the galactic centre has recently been observed in the Fermi-LAT data. This signal can be interpreted as resulting from WIMP annihilation, with the spectrum well-fit by dark matter annihilating…

High Energy Physics - Phenomenology · Physics 2015-05-13 Tony Gherghetta , Benedict von Harling , Anibal D. Medina , Michael A. Schmidt , Timothy Trott

The recombination history of the Universe provides a useful tool for constraining the annihilation of dark matter particles. Even a small fraction of dark matter particles annihilated during the cosmic dark age can provide sufficient energy…

Astrophysics · Physics 2008-11-26 Le Zhang , Xuelei Chen , Yi-An Lei , Zongguo Si

Light dark matter annihilating into electron-positron pairs emits a significant amount of internal bremsstrahlung that may contribute to the cosmic gamma-ray background. The amount of emitted gamma-rays depends on the dark matter clumping…

The self-annihilation of dark matter particles with mass in the MeV range can produce gamma rays via prompt or secondary radiation. The annihilation rate for such light dark matter particles is however tightly constrained by cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-04 Alma X. Gonzalez-Morales , Stefano Profumo , Javier Reynoso-Córdova