scholarly journals Unitarity limits on thermal dark matter in (non-)standard cosmologies

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Disha Bhatia ◽  
Satyanarayan Mukhopadhyay
Keyword(s):  
Dark Matter ◽  
Big Bang ◽  
Reaction Cross ◽  
Annihilation Rate ◽  
Dark Sector ◽  
Big Bang Nucleosynthesis ◽  
Complex Scalar ◽  
Intermediate Period ◽  
Inelastic Reaction ◽  
Relic Abundance

Abstract Using the upper bound on the inelastic reaction cross-section implied by S-matrix unitarity, we derive the thermally averaged maximum dark matter (DM) annihilation rate for general k → 2 number-changing reactions, with k ≥ 2, taking place either entirely within the dark sector, or involving standard model fields. This translates to a maximum mass of the particle saturating the observed DM abundance, which, for dominantly s-wave annihilations, is obtained to be around 130 TeV, 1 GeV, 7 MeV and 110 keV, for k = 2, 3, 4 and 5, respectively, in a radiation dominated Universe, for a real or complex scalar DM stabilized by a minimal symmetry. For modified thermal histories in the pre-big bang nucleosynthesis era, with an intermediate period of matter domination, values of reheating temperature higher than $$ \mathcal{O}(200) $$ O 200 GeV for k ≥ 4, $$ \mathcal{O}(1) $$ O 1 TeV for k = 3 and $$ \mathcal{O}(50) $$ O 50 TeV for k = 2 are strongly disfavoured by the combined requirements of unitarity and DM relic abundance, for DM freeze-out before reheating.

scholarly journals The building blocks of the universe

2021 ◽  
Vol 77 (3) ◽  
Author(s):  
Anslyn J. John
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Building Blocks ◽  
Big Bang ◽  
The State ◽  
Dark Sector ◽  
Big Bang Nucleosynthesis ◽  
Ordinary Matter ◽  
Special Collection ◽  
The Universe

I review the state of knowledge of the composition of the universe for a non-specialist audience. The universe is built up of four components. These are radiation, baryonic (ordinary) matter, dark matter and dark energy. In this article, a quick outline of the theory of Big Bang nucleosynthesis is presented, and the origin of the elements is explained. Cosmology requires the presence of dark matter, which forms most of the mass of the universe, and dark energy, which drives the acceleration of the expansion. The dark sector is motivated, and possible explanations are stated.Contribution: As part of this special collection on building blocks, the building blocks of the universe are discussed and unsolved problems and proposed solutions are highlighted.

scholarly journals A first order dark SU(2) D phase transition with vector dark matter in the light of NANOGrav 12.5 yr data

2021 ◽  
Vol 2021 (12) ◽  
pp. 039
Author(s):  
Debasish Borah ◽  
Arnab Dasgupta ◽  
Sin Kyu Kang
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Scalar Potential ◽  
Dark Sector ◽  
Complex Scalar ◽  
First Order ◽  
First Order Phase Transition ◽  
Vector Bosons ◽  
Relic Abundance ◽  
First Order Phase

Abstract We study a dark SU(2) D gauge extension of the standard model (SM) with the possibility of a strong first order phase transition (FOPT) taking place below the electroweak scale in the light of NANOGrav 12.5 yr data. As pointed out recently by the NANOGrav collaboration, gravitational waves (GW) from such a FOPT with appropriate strength and nucleation temperature can explain their 12.5 yr data. We impose a classical conformal invariance on the scalar potential of SU(2) D sector involving only a complex scalar doublet with negligible couplings with the SM Higgs. While a FOPT at sub-GeV temperatures can give rise to stochastic GW around nano-Hz frequencies being in agreement with NANOGrav findings, the SU(2) D vector bosons which acquire masses as a result of the FOPT in dark sector, can also serve as dark matter (DM) in the universe. The relic abundance of such vector DM can be generated in a non-thermal manner from the SM bath via scalar portal mixing. We also discuss future sensitivity of gravitational wave experiments to the model parameter space.

scholarly journals Big-bang nucleosynthesis and the relic abundance of dark matter in a stau-neutralino coannihilation scenario

2008 ◽  
Vol 78 (5) ◽  
Author(s):  
Toshifumi Jittoh ◽  
Kazunori Kohri ◽  
Masafumi Koike ◽  
Joe Sato ◽  
Takashi Shimomura ◽  
...  
Keyword(s):  
Dark Matter ◽  
Big Bang ◽  
Big Bang Nucleosynthesis ◽  
Relic Abundance

scholarly journals Cannibalism's lingering imprint on the matter power spectrum

2022 ◽  
Vol 2022 (01) ◽  
pp. 017
Author(s):  
Adrienne L. Erickcek ◽  
Pranjal Ralegankar ◽  
Jessie Shelton
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Big Bang ◽  
Small Scale ◽  
Thermal Bath ◽  
Dark Sector ◽  
Big Bang Nucleosynthesis ◽  
Particle Properties ◽  
Matter Power Spectrum ◽  
Expansion Of The Universe

Abstract The early universe may have contained internally thermalized dark sectors that were decoupled from the Standard Model. In such scenarios, the relic dark thermal bath, composed of the lightest particle in the dark sector, can give rise to an epoch of early matter domination prior to Big Bang Nucleosynthesis, which has a potentially observable impact on the smallest dark matter structures. This lightest dark particle can easily and generically have number-changing self-interactions that give rise to “cannibal” behavior. We consider cosmologies where an initially sub-dominant cannibal species comes to temporarily drive the expansion of the universe, and we provide a simple map between the particle properties of the cannibal species and the key features of the enhanced dark matter perturbation growth in such cosmologies. We further demonstrate that cannibal self-interactions can determine the small-scale cutoff in the matter power spectrum even when the cannibal self-interactions freeze out prior to cannibal domination.

COSMOLOGICAL PROMISING PARAMETERS OF STAU IN THE MINIMAL SUPERSYMMETRIC STANDARD MODEL

2009 ◽  
Vol 24 (18n19) ◽  
pp. 3501-3507
Author(s):  
TOSHIFUMI JITTOH ◽  
KAZUNORI KOHRI ◽  
MASAFUMI KOIKE ◽  
JOE SATO ◽  
TAKASHI SHIMOMURA ◽  
...  
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Minimal Supersymmetric Standard Model ◽  
Mass Difference ◽  
Big Bang ◽  
Big Bang Nucleosynthesis ◽  
Primordial Abundance ◽  
Relic Abundance ◽  
The Big Bang

We find that we can account for the possible descrepancy of the primordial abundance of 7 Li between the observation and the prediction of the Big-Bang Nucleosynthesis in a scenario of the Big-Bang Nucleosynthesis with the Minimal Supersymmetric Standard Model. This scenario is consistent with a stau-neutralino coannihilation scenario to explain the relic abundance of dark matter. The solution to the discrepancy is given by taking the values of parameters; the mass of the neutralino as 300 GeV and the mass difference between the stau and the neutralino as (100 – 120) MeV.

scholarly journals Xenon-1T excess as a possible signal of a sub-GeV hidden sector dark matter

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Amin Aboubrahim ◽  
Michael Klasen ◽  
Pran Nath
Keyword(s):  
Dark Matter ◽  
Particle Physics ◽  
Small Mass ◽  
Big Bang ◽  
Mass Splitting ◽  
Recoil Energy ◽  
Dirac Fermions ◽  
Dark Sector ◽  
Dark Photon ◽  
Physics Model

Abstract We present a particle physics model to explain the observed enhancement in the Xenon-1T data at an electron recoil energy of 2.5 keV. The model is based on a U(1) extension of the Standard Model where the dark sector consists of two essentially mass degenerate Dirac fermions in the sub-GeV region with a small mass splitting interacting with a dark photon. The dark photon is unstable and decays before the big bang nucleosynthesis, which leads to the dark matter constituted of two essentially mass degenerate Dirac fermions. The Xenon-1T excess is computed via the inelastic exothermic scattering of the heavier dark fermion from a bound electron in xenon to the lighter dark fermion producing the observed excess events in the recoil electron energy. The model can be tested with further data from Xenon-1T and in future experiments such as SuperCDMS.

scholarly journals Dark matter annihilation in the universe

2014 ◽  
Vol 30 ◽  
pp. 1460256 ◽  
Author(s):  
Pierre Salati
Keyword(s):  
Dark Matter ◽  
Galactic Halo ◽  
Light Element ◽  
Big Bang ◽  
Microwave Background ◽  
Dark Matter Annihilation ◽  
Element Abundances ◽  
Primordial Plasma ◽  
Relic Abundance ◽  
The Universe

The astronomical dark matter is an essential component of the Universe and yet its nature is still unresolved. It could be made of neutral and massive elementary particles which are their own antimatter partners. These dark matter species undergo mutual annihilations whose effects are briefly reviewed in this article. Dark matter annihilation plays a key role at early times as it sets the relic abundance of the particles once they have decoupled from the primordial plasma. A weak annihilation cross section naturally leads to a cosmological abundance in agreement with observations. Dark matter species subsequently annihilate — or decay — during Big Bang nucleosynthesis and could play havoc with the light element abundances unless they offer a possible solution to the 7 Li problem. They could also reionize the intergalactic medium after recombination and leave visible imprints in the cosmic microwave background. But one of the most exciting aspects of the question lies in the possibility to indirectly detect the dark matter species through the rare antimatter particles — antiprotons, positrons and antideuterons — which they produce as they currently annihilate inside the galactic halo. Finally, the effects of dark matter annihilation on stars is discussed.

scholarly journals Impact of neutrino properties and dark matter on the primordial Lithium production

2019 ◽  
Vol 28 (08) ◽  
pp. 1950065 ◽  
Author(s):  
Tahani R. Makki ◽  
Mounib F. El Eid ◽  
Grant J. Mathews
Keyword(s):  
Dark Matter ◽  
Early Universe ◽  
Nuclear Physics ◽  
Big Bang ◽  
Light Elements ◽  
Big Bang Nucleosynthesis ◽  
Chemical Potentials ◽  
The Creation ◽  
The Universe

The light elements and their isotopes were produced during standard big bang nucleosynthesis (SBBN) during the first minutes after the creation of the universe. Comparing the calculated abundances of these light species with observed abundances, it appears that all species match very well except for lithium (7Li) which is overproduced by the SBBN. This discrepancy is rather challenging for several reasons to be considered on astrophysical and on nuclear physics ground, or by invoking nonstandard assumptions which are the focus of this paper. In particular, we consider a variation of the chemical potentials of the neutrinos and their temperature. In addition, we investigated the effect of dark matter on 7Li production. We argue that including nonstandard assumptions can lead to a significant reduction of the 7Li abundance compared to that of SBBN. This aspect of lithium production in the early universe may help to resolve the outstanding cosmological lithium problem.

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