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We use H.E.S.S. $\gamma$-ray observations of Sgr A* to derive novel limits on the Dark Matter (DM) annihilation cross-section. We quantify their dependence on uncertainties i) in the DM halo profile, which we vary from peaked to cored, and…

High Energy Physics - Phenomenology · Physics 2023-09-14 Shyam Balaji , Divya Sachdeva , Filippo Sala , Joseph Silk

In this work we study the constraints on dark matter (DM) annihilation/decay from the Fermi-LAT Isotropic Gamma-Ray Background (IGRB) observation. We consider the contributions from both extragalactic and galactic DM components. For DM…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-26 Wei Liu , Xiao-Jun Bi , Su-Jie Lin , Peng-Fei Yin

Gas-rich dwarf galaxies located outside the virial radius of their host are relatively pristine systems and have ultra-low gas cooling rates. This makes them very sensitive to heat injection by annihilation or decay of dark matter (DM).…

High Energy Physics - Phenomenology · Physics 2022-10-12 Digvijay Wadekar , Zihui Wang

Kinematically forbidden channels can set the freeze-out dark matter (DM) relic abundance. These channels are described by DM annihilations into heavier states, which vanish at zero temperature limit, but occur at finite temperatures in the…

High Energy Physics - Phenomenology · Physics 2022-11-30 Kwei-Chou Yang

The excess above 1 GeV in the energy spectrum of the diffuse Galactic gamma radiation, measured with the EGRET experiment, can be interpreted as the annihilation of Dark Matter (DM) particles. The DM is distributed in a halo around the…

Astrophysics · Physics 2007-10-29 Markus Weber

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

The annihilation of dark matter particles in the galactic halo of the Milky Way may lead to cosmic ray signatures that can be probed by the AMS-02 experiment, which has measured the composition and fluxes of charged cosmic rays with…

High Energy Physics - Phenomenology · Physics 2017-05-10 Leila Ali Cavasonza , Henning Gast , Michael Krämer , Mathieu Pellen , Stefan Schael

The AMS-02 collaboration has recently presented measurements of excellent quality of the cosmic electron and positron fluxes as well as the positron fraction. We use the measurements of the positron flux to derive, for the first time,…

High Energy Physics - Phenomenology · Physics 2014-04-02 Alejandro Ibarra , Anna S. Lamperstorfer , Joseph Silk

We present updated constraints on 'light' Dark Matter (DM) particles with masses between 1 MeV and 5 GeV. In this range, we can expect DM-produced $e^\pm$ pairs to up-scatter low-energy ambient photons in the Milky Way via the Inverse…

High Energy Physics - Phenomenology · Physics 2024-01-17 Jordan Koechler

Dark matter annihilation into charged particles is necessarily accompanied by gamma rays, produced via radiative corrections. Internal bremsstrahlung from the final state particles can produce hard gamma rays up to the dark matter mass,…

Astrophysics · Physics 2010-02-01 Nicole F. Bell , Thomas D. Jacques

We present a new method to measure or constrain p-wave-suppressed cross sections for dark matter (DM) annihilations inside the steep density spikes induced by supermassive black holes. We demonstrate that the high DM densities, together…

High Energy Astrophysical Phenomena · Physics 2015-12-09 Jessie Shelton , Stuart L. Shapiro , Brian D. Fields

At the tail of its velocity distribution, cold dark matter (DM) can annihilate at finite temperature to states heavier than itself. We explore the possibility that DM freezeout is dictated by these "forbidden annihilations" at the…

High Energy Physics - Phenomenology · Physics 2017-02-15 Antonio Delgado , Adam Martin , Nirmal Raj

Electrons and positrons produced in dark matter annihilation can generate secondary emission through synchrotron and IC processes, and such secondary emission provides a possible means to detect DM particles with masses beyond the…

High Energy Astrophysical Phenomena · Physics 2024-02-02 Xiao-Song Hu , Ben-Yang Zhu , Tian-Ci Liu , Yun-Feng Liang

Indirect searches for dark matter through Standard Model products of its annihilation generally assume a cross-section which is dominated by a term independent of velocity ($s$-wave annihilation). However, in many DM models an $s$-wave…

High Energy Astrophysical Phenomena · Physics 2019-05-29 Christian Johnson , Regina Caputo , Chris Karwin , Simona Murgia , Steve Ritz , Jessie Shelton

We study a light thermal scalar dark matter (DM) model with a light scalar mediator mixed with the standard model Higgs boson, including both the theoretical bounds and the current experimental constraints. The thermal scalar DM with the…

High Energy Physics - Phenomenology · Physics 2022-03-14 Tomoya Hara , Shinya Kanemura , Taisuke Katayose

In the simplest models of asymmetric dark matter (ADM) annihilation signals are not expected, since the DM is non-self-conjugate and the relic density of anti-DM is negligible. We investigate a new class of models in which a symmetric DM…

High Energy Physics - Phenomenology · Physics 2014-09-02 Edward Hardy , Robert Lasenby , James Unwin

In warm dark matter scenarios structure formation is suppressed on small scales with respect to the cold dark matter case, reducing the number of low-mass halos and the fraction of ionized gas at high redshifts and thus, delaying…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-24 Laura Lopez-Honorez , Olga Mena , Sergio Palomares-Ruiz , Pablo Villanueva Domingo

Cosmic microwave background (CMB) constraints on dark matter annihilation are a uniquely powerful tool in the quest to understand the nature of dark matter. Annihilation of dark matter to Standard Model particles between recombination and…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-24 Daniel Green , P. Daniel Meerburg , Joel Meyers

The cosmic electron and positron excesses have been explained as possible dark matter (DM) annihilation products. In this work we investigate the possible effects of such a DM annihilation scenario during the evolution history of the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Qiang Yuan , Bin Yue , Xiaojun Bi , Xuelei Chen , Xinmin Zhang

Dark matter (DM) could be a relic of freeze-in through a light mediator, where the DM is produced by extremely feeble, IR-dominated processes in the thermal Standard Model plasma. In the simplest viable models with the DM mass below the MeV…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-15 Cora Dvorkin , Tongyan Lin , Katelin Schutz