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Alternative cosmologies, based on extensions of General Relativity, predict modified thermal histories in the Early Universe during the pre Big Bang Nucleosynthesis (BBN) era, epoch which is not directly constrained by cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 R. Catena , N. Fornengo , M. Pato , L. Pieri , A. Masiero

We consider a modification to the standard cosmological history consisting of introducing a new species $\phi$ whose energy density red-shifts with the scale factor $a$ like $\rho_\phi \propto a^{-(4+n)}$. For $n>0$, such a red-shift is…

High Energy Physics - Phenomenology · Physics 2017-05-09 Francesco D'Eramo , Nicolas Fernandez , Stefano Profumo

We show that the relic abundance of the minority component of asymmetric dark matter can be very sensitive to the expansion rate of the Universe and the temperature of transition between a non-standard pre-Big Bang Nucleosynthesis…

High Energy Physics - Phenomenology · Physics 2015-06-15 Graciela B. Gelmini , Ji-Haeng Huh , Thomas Rehagen

Standard lore states that there is tension between the need to accommodate the relic density of a weakly interacting massive particle and direct searches for dark matter. However, the estimation of the relic density rests on an…

High Energy Physics - Phenomenology · Physics 2020-08-03 Dillon Berger , Seyda Ipek , Tim M. P. Tait , Michael Waterbury

Measurements of the primordial element abundances provide us with an important probe of our universe's early thermal history, allowing us to constrain the expansion rate and composition of our universe as early as $\sim 1 \, {\rm s}$ after…

High Energy Physics - Phenomenology · Physics 2023-10-10 Dan Hooper , Huangyu Xiao

The light relic density affects the thermal and expansion history of the early Universe leaving a number of observable imprints. We focus on the primordial abundances of light elements produced during the process of Big Bang nucleosynthesis…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-19 Alex Laguë , Joel Meyers

The standard theoretical estimation of the thermal dark matter abundance may be significantly altered if properties of dark matter particles in the early universe and at the present cosmological epoch differ. This may happen if, e.g., a…

High Energy Physics - Phenomenology · Physics 2020-04-01 Archil Kobakhidze , Michael A. Schmidt , Matthew Talia

A new theoretical framework for computation of the relic abundance of cold dark matter particles such as LSP is presented and some generic features of new results are discussed. The most important is a generalization of the Boltzmann…

High Energy Physics - Phenomenology · Physics 2016-11-03 M. Yoshimura

We investigate the production of neutralino dark matter in a cosmological scenario featuring an early matter dominated era ending at a relatively low reheating temperature. In such scenarios different production mechanisms of weakly…

High Energy Physics - Phenomenology · Physics 2018-12-18 Manuel Drees , Fazlollah Hajkarim

We investigate dark matter (DM) production in an early matter dominated era where a heavy long-lived particle decays to radiation and DM. In addition to DM annihilation into and thermal DM production from radiation, we include direct DM…

High Energy Physics - Phenomenology · Physics 2018-03-15 Manuel Drees , Fazlollah Hajkarim

We study the general properties of the freezeout of a thermal relic. We give analytic estimates of the relic abundance for an arbitrary freezeout process, showing when instantaneous freezeout is appropriate and how it can be corrected when…

High Energy Physics - Phenomenology · Physics 2024-04-09 Ronny Frumkin , Eric Kuflik , Itay Lavie , Tal Silverwater

This conference proceedings paper provides a short summary of the constraints presented in Menci et al. 2016, 2017 on the mass of thermal WDM candidates, and of the results presented in Romanello et al. 2021 on how Reionization scenarios…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-11 Marco Castellano , Nicola Menci , Massimiliano Romanello

We investigate the relic abundance of dark matter from coannihilation in non-standard cosmological scenarios. We explore the effect of coannihilation on the relic density of dark matter and freeze out temperature in quintessence model with…

High Energy Physics - Phenomenology · Physics 2024-02-13 Fangyu Liu , Hoernisa Iminniyaz

The thermal history of the universe before the epoch of nucleosynthesis is unknown. The maximum temperature in the radiation-dominated era, which we will refer to as the reheat temperature, may have been as low as 0.7 MeV. In this paper we…

High Energy Physics - Phenomenology · Physics 2009-10-31 Gian Francesco Giudice , Edward W. Kolb , Antonio Riotto

In the standard thermal relic scenario, dark matter remains in chemical equilibrium with the Standard Model radiation bath until freeze-out occurs at $T \sim m_X/20$, where $m_X$ is the dark matter mass. In this familiar class of models,…

High Energy Physics - Phenomenology · Physics 2026-05-20 Dan Hooper , Gordan Krnjaic , Gabriele Montefalcone

The generation of a kination-dominated phase by a quintessential exponential model is investigated and the parameters of the model are restricted so that a number of observational constraints (originating from nucleosynthesis, the present…

High Energy Physics - Phenomenology · Physics 2011-07-19 C. Pallis

Weakly Interactive Massive Particles (WIMPs) are the most widely studied candidate particles forming the cold dark matter (CDM) whose existence can be inferred from a wealth of astrophysical and cosmological observations. In the framework…

High Energy Physics - Phenomenology · Physics 2017-01-24 Manuel Drees , Fazlollah Hajkarim , Ernany Rossi Schmitz

The generation of an early kination dominated era within a tracking quintessential model is investigated, the relic density of the Weakly Interacting Massive Particles (WIMPs) is calculated and we show that it can be enhanced with respect…

High Energy Physics - Phenomenology · Physics 2010-07-27 C. Pallis

We discuss strategies to make inferences on the thermal relic abundance of a Weakly Interacting Massive Particle (WIMP) when the same effective dimension-six operator that explains an experimental excess in direct detection is assumed to…

High Energy Physics - Phenomenology · Physics 2017-04-25 Stefano Scopel , Hyeonhye Yu

We show that the relic abundance of thermal dark matter annihilating via a long-range interaction, is significantly affected by the formation and decay of dark matter bound states in the early universe, if the dark matter mass is above a…

High Energy Physics - Phenomenology · Physics 2015-01-15 Benedict von Harling , Kalliopi Petraki