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The properties of the dark matter that determine its thermal relic abundance can be very different from the dark matter properties today. We investigate this possibility by coupling a dark matter sector to a scalar that undergoes a phase…

High Energy Physics - Phenomenology · Physics 2008-12-16 Timothy Cohen , David E. Morrissey , Aaron Pierce

We explore a class of dark matter models with two dark matter candidates, only one interacts with the standard model sector. One of the dark matter is thermalized with the assistance of the other stable particle. While both stable particles…

High Energy Physics - Phenomenology · Physics 2015-06-03 Genevieve Belanger , Jong-Chul Park

If dark matter decay or annihilate, a large amount of energy and particles would be released into the cosmic plasma. Therefore, they could modify the thermal and ionization history of our universe, then leave footprints on the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-22 Lu Chen , Ke Wang

Neutralino as the lightest supersymmetric particle (LSP) is a candidate for supersymmetric dark matter. It is known that coannihilation effects could be important in neutralino relic density calculation. Here we present some results on…

High Energy Physics - Phenomenology · Physics 2009-11-07 Yudi Santoso

Sub-GeV dark matter is an appealing thermal target because it can still be produced via the standard freeze-out mechanism; at such low masses, achieving freeze-out naturally points to the presence of a light mediator, which shifts the most…

High Energy Physics - Phenomenology · Physics 2026-01-15 Tatsuya Aonashi , Shigeki Matsumoto , Yu Watanabe , Yuki Watanabe

The particle-physics nature of dark matter (DM) remains one of the central open questions in modern physics. A widely used framework to investigate DM properties is provided by simplified models (DMSimps), which extend the Standard Model…

High Energy Physics - Phenomenology · Physics 2025-10-13 Mattia Di Mauro , Bohan Xie

The identity of Dark Matter (DM) is one of the most captivating topics in particle physics today. The R-parity conserving Minimal Supersymmetric Standard Model (MSSM), which naturally provides a DM candidate in the form of the lightest…

High Energy Physics - Phenomenology · Physics 2018-01-15 Carlos Ávila , Andrés Flórez , Alfredo Gurrola , Dale Julson , Savanna Starko

We explore the detection prospects for a minimal secluded dark matter model, where a fermionic dark matter particle interacts with the Standard Model (SM) via a kinetically mixed dark photon. We focus on scenarios where the dark photon…

High Energy Physics - Phenomenology · Physics 2026-01-29 Ahmed Alenezi , Cari Cesarotti , Stefania Gori , Jessie Shelton

In standard cosmology, the growth of structure becomes significant following matter-radiation equality. In non-thermal histories, where an effectively matter-dominated phase occurs due to scalar oscillations prior to Big Bang…

High Energy Physics - Phenomenology · Physics 2016-09-14 Adrienne L. Erickcek , Kuver Sinha , Scott Watson

We demonstrate that if the dark matter (DM) in the Universe contains multiple components,the interactions between the DM components may induce DM conversions. It is then possible that the lightest DM component with an annihilation cross…

High Energy Physics - Phenomenology · Physics 2011-10-11 Ze-Peng Liu , Yue-Liang Wu , Yu-Feng Zhou

Different mechanisms operate in various regions of the MSSM parameter space to bring the relic density of the lightest neutralino, neutralino_1, assumed here to be the LSP and thus the Dark Matter (DM) particle, into the range allowed by…

The status of the constrained minimal supersymmetric standard model (CMSSM) will be discussed in light of our current understanding of the relic density after WMAP. A global likelihood analysis of the model is performed including data from…

High Energy Physics - Phenomenology · Physics 2007-05-23 Keith A. Olive

The freeze-in mechanism provides a compelling framework for dark matter (DM) production, particularly suited to scenarios involving feeble interactions with the Standard Model (SM). In this work, we highlight a possible interplay of a…

High Energy Physics - Phenomenology · Physics 2025-06-12 Nicolás Bernal , Esau Cervantes , Kuldeep Deka , Andrzej Hryczuk

Structure formation with cold dark matter (CDM) predicts halos with a central density cusp, which are observationally disfavored. If CDM particles have an annihilation cross section sigma*v ~ 10**(-29) (m/GeV) cm**2, then annihilations will…

Astrophysics · Physics 2010-04-06 M. Kaplinghat , L. Knox , M. S. Turner

Pure singlets are typically disfavored as dark matter candidates, since they generically have a thermal relic abundance larger than the observed value. In this paper, we propose a new dark matter mechanism called "assimilation", which takes…

High Energy Physics - Phenomenology · Physics 2012-03-08 Francesco D'Eramo , Lin Fei , Jesse Thaler

Biswas et al. found that the thermal relic density of a dark matter particle freezing out while the universe's energy density is dominated by a non-standard extra component $\phi$, whose energy density redshifts faster than radiation, can…

High Energy Physics - Phenomenology · Physics 2019-01-14 Nicolas Fernandez , Stefano Profumo

Inspired by our recent paper "reshuffled SIMP dark matter", we notice that the reaction rate of the two-loop induced $2 \to 2$ process may dominate over or be comparable with that of the $3 \to 2$ process at the chemical freezeout of…

High Energy Physics - Phenomenology · Physics 2021-08-17 Shu-Yu Ho , Chih-Ting Lu

We show that a recently constructed five-dimensional (5D) model with gauge-Higgs unification and explicit Lorentz symmetry breaking in the bulk, provides a natural dark matter candidate. This is the lightest Kaluza-Klein particle odd under…

High Energy Physics - Phenomenology · Physics 2010-10-27 Marco Regis , Marco Serone , Piero Ullio

Freeze-in of multi-component dark sectors is governed not only by the interaction with the thermal plasma, but also by their internal dynamics. Full thermalisation within the dark sector is not guaranteed, raising the question of impact of…

High Energy Physics - Phenomenology · Physics 2026-04-17 Shiuli Chatterjee , Andrzej Hryczuk

Terascale supersymmetry has the potential to provide a natural explanation of the dominant dark matter component of the standard lambda-CDM cosmology. However once we impose the constraints on minimal supersymmetry parameters from current…

High Energy Physics - Phenomenology · Physics 2009-11-11 Gabriela Barenboim , Joseph Lykken