scholarly journals Probes for 4th Generation Constituents of Dark Atoms in Higgs Boson Studies at the LHC

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
M. Yu. Khlopov ◽  
R. M. Shibaev
Keyword(s):  
Dark Matter ◽  
Higgs Boson ◽  
Big Bang ◽  
Decay Rates ◽  
Neutral Atoms ◽  
Big Bang Nucleosynthesis ◽  
Charged Species ◽  
The Difference ◽  
The Universe ◽  
Direct Dark Matter

The nonbaryonic dark matter of the Universe can consist of new stable charged species, bound in heavy neutral “atoms” by ordinary Coulomb interaction. StableU-(anti-U)quarks of 4th generation, bound in stable colorless(U- U- U-)clusters, are captured by the primordial helium, produced in Big Bang Nucleosynthesis, thus forming neutral “atoms” of O-helium (OHe), a specific nuclear interacting dark matter that can provide solution for the puzzles of direct dark matter searches. However, the existence of the 4th generation quarks and leptons should influence the production and decay rates of Higgs boson and is ruled out by the experimental results of the Higgs boson searches at the LHC, if the Higgs boson coupling to 4th generation fermions is not suppressed. Here, we argue that the difference between the three known quark-lepton families and the 4th family can naturally lead to suppression of this coupling, relating the accelerator test for such a composite dark matter scenario to the detailed study of the production and modes of decay of the 125.5 GeV boson, discovered at the LHC.

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.

scholarly journals Dark matter freeze-out during matter domination

2018 ◽  
Vol 33 (29) ◽  
pp. 1850181 ◽  
Author(s):  
Saleh Hamdan ◽  
James Unwin
Keyword(s):  
Dark Matter ◽  
Energy Density ◽  
Big Bang ◽  
Big Bang Nucleosynthesis ◽  
Hubble Rate ◽  
Dark Matter Relic Density ◽  
Relic Density ◽  
The Masses ◽  
The Universe ◽  
Freeze Out

We highlight the general scenario of dark matter freeze-out while the energy density of the universe is dominated by a decoupled non-relativistic species. Decoupling during matter domination changes the freeze-out dynamics, since the Hubble rate is parametrically different for matter and radiation domination. Furthermore, for successful Big Bang Nucleosynthesis the state dominating the early universe energy density must decay, this dilutes (or repopulates) the dark matter. As a result, the masses and couplings required to reproduce the observed dark matter relic density can differ significantly from radiation-dominated freeze-out.

scholarly journals Big Bang Nucleosynthesis in Visible and Hidden-Mirror Sectors

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Paolo Ciarcelluti
Keyword(s):  
Dark Matter ◽  
Building Blocks ◽  
Big Bang ◽  
Dark Matter Candidate ◽  
Big Bang Nucleosynthesis ◽  
Enhanced Production ◽  
The Standard Model ◽  
The Big Bang ◽  
The Universe ◽  
Mirror Matter

One of the still viable candidates for the dark matter is the so-called mirror matter. Its cosmological and astrophysical implications were widely studied, pointing out the importance to go further with research. In particular, the Big Bang nucleosynthesis provides a strong test for every dark matter candidate, since it is well studied and involves relatively few free parameters. The necessity of accurate studies of primordial nucleosynthesis with mirror matter has then emerged. I present here the results of accurate numerical simulations of the primordial production of both ordinary nuclides and nuclides made of mirror baryons, in presence of a hidden mirror sector with unbroken parity symmetry and with gravitational interactions only. These elements are the building blocks of all the structures forming in the Universe; therefore, their chemical composition is a key ingredient for astrophysics with mirror dark matter. The production of ordinary nuclides shows differences from the standard model for a ratio of the temperatures between mirror and ordinary sectorsx=T′/T≳0.3, and they present an interesting decrease of the abundance ofLi7. For the mirror nuclides, instead, one observes an enhanced production ofHe4, which becomes the dominant element forx≲0.5, and much larger abundances of heavier elements.

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 The Higgs boson and cosmology

2015 ◽  
Vol 373 (2032) ◽  
pp. 20140038 ◽  
Author(s):  
Mikhail Shaposhnikov
Keyword(s):  
Dark Matter ◽  
Higgs Boson ◽  
Standard Model ◽  
Structure Formation ◽  
Higgs Field ◽  
Big Bang ◽  
Seed Structure ◽  
Matter Production ◽  
The Standard Model ◽  
The Universe

I will discuss how the Higgs field of the Standard Model may have played an important role in cosmology, leading to the homogeneity, isotropy and flatness of the Universe; producing the quantum fluctuations that seed structure formation; triggering the radiation-dominated era of the hot Big Bang; and contributing to the processes of baryogenesis and dark matter production.

scholarly journals Outstanding questions: physics beyond the Standard Model

2012 ◽  
Vol 370 (1961) ◽  
pp. 818-830 ◽  
Author(s):  
John Ellis
Keyword(s):  
Dark Matter ◽  
Higgs Boson ◽  
Large Hadron Collider ◽  
Standard Model ◽  
Particle Physics ◽  
Hadron Collider ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
The Difference ◽  
The Universe

The Standard Model of particle physics agrees very well with experiment, but many important questions remain unanswered, among them are the following. What is the origin of particle masses and are they due to a Higgs boson? How does one understand the number of species of matter particles and how do they mix? What is the origin of the difference between matter and antimatter, and is it related to the origin of the matter in the Universe? What is the nature of the astrophysical dark matter? How does one unify the fundamental interactions? How does one quantize gravity? In this article, I introduce these questions and discuss how they may be addressed by experiments at the Large Hadron Collider, with particular attention to the search for the Higgs boson and supersymmetry.

scholarly journals Constraints on Dark Matter from Primordial Nucleosynthesis

1987 ◽  
Vol 117 ◽  
pp. 499-523
Author(s):  
Jean Audouze
Keyword(s):  
Dark Matter ◽  
Chemical Evolution ◽  
Big Bang ◽  
Baryon Density ◽  
Cosmological Parameter ◽  
Big Bang Nucleosynthesis ◽  
Primordial Nucleosynthesis ◽  
The Galaxy ◽  
Predicted Values ◽  
The Universe

Primordial nucleosynthesis which is responsible for the formation of the lightest elements (D, 3He, 4He and 7Li) provides a unique way to determine the present baryon density pB in the Universe and therefore the corresponding cosmological parameter ΩB. After a brief summary of the relevant abundance determinations and of the consequences of the Standard Big Bang nucleosynthesis, it is argued that one needs to call for specific models of chemical evolution of the Galaxy in order to reconcile the observations with the predictions of this model. In this context the predicted values for ΩB should range from 4 10−3 to 6 10−2. These values are significantly lower than those deduced from current M/L determinations.

Constraints on the density of baryons in the Universe

1982 ◽  
Vol 307 (1497) ◽  
pp. 43-54 ◽  
Keyword(s):  
Dark Matter ◽  
Lower Limit ◽  
Small Groups ◽  
Big Bang ◽  
Baryon Density ◽  
Small Range ◽  
Big Bang Nucleosynthesis ◽  
Groups Of Galaxies ◽  
Best Fit ◽  
The Universe

It is shown that not only does Big Bang nucleosynthesis provide an upper limit on the baryon density of the Universe, but if one takes into account arguments concerning the production of 3 He in stars, one can show that the 3 He plus deuterium abundance can also provide a lower limit on the baryon density of the Universe. The derived constraints are that the baryon: photon ratio, y, must be between 1.5 x 10- 10 and 7 x 10 -9 with a best fit between 3 and 6 x 10 -10 . This small range for y has implications for our limits on numbers of neutrino types, for Big Bang baryosynthesis, and for arguments about the nature of the dark matter in clusters of galaxies. With reference to the dark matter, the derived baryon density for Big Bang nucleosynthesis corresponds very closely with the implied density of matter in binaries and small groups of galaxies. This implies that non-baryonic matter is not dominant by a large factor on scales as large as binaries and small groups of galaxies. It is also shown that the constraints on the lower limit on the baryon density constrain the lower limit on the primordial 4He abundance. Consistency seems to be possible only if the primordial 4 He is between 23 and 25 % by mass if there are three or four species of neutrinos.

IS NEUTRALINO DARK MATTER POSSIBLE IN THE SUPERSTRING THEORY?

2004 ◽  
Vol 13 (05) ◽  
pp. 819-830 ◽  
Author(s):  
M. D. POLLOCK
Keyword(s):  
Dark Matter ◽  
Big Bang ◽  
Superstring Theory ◽  
Big Bang Nucleosynthesis ◽  
State Formula ◽  
Model Independent ◽  
Age Of The Universe ◽  
Invisible Axion ◽  
High Level ◽  
The Universe

In the heterotic superstring theory, the decay constant of the QCD axion lies within the range 3×1016≲fa GeV ≲1018, the lower limit referring to the model-independent axion, while the upper limit is due to dimension-five, non-renormalizable effects first calculated by Cvetič. Consequently, the neutralino χ0, assumed to be a nearly pure B-ino, decays into the axino ã on the time scale obtained by Covi et al., [Formula: see text], which is ≲10-3 times the age of the Universe t0≈4×1017 s , but can only be made less than the time t≈1 s of the onset of Big-Bang nucleosynthesis by revising mχ0 to an unnaturally high level, mχ0≳500 TeV . Therefore, it is necessary to set the coefficient Ca YY =0, which is possible for the Kim–Shifman–Vainshtein–Zakharov invisible-axion model if the electric charge q c of the heavy-quark colour representation C vanishes. The neutralino does not then decay and can constitute some fraction of the dark matter of the Universe, depending upon the value of mχ0 (for a gaugino-dominated state, [Formula: see text] where [Formula: see text] is the SU(2) singlet slepton). The consequences of an ultra-light axion with fa≈1018 GeV are also discussed.

scholarly journals Searching for space-time variation of the fine structure constant using QSO spectra: overview and future prospects

2009 ◽  
Vol 5 (H15) ◽  
pp. 304-304
Author(s):  
J. C. Berengut ◽  
V. A. Dzuba ◽  
V. V. Flambaum ◽  
J. A. King ◽  
M. G. Kozlov ◽  
...  
Keyword(s):  
Nuclear Reactor ◽  
Structure Constant ◽  
Big Bang ◽  
The Other ◽  
Fine Structure Constant ◽  
Spatial And Temporal Variation ◽  
Fundamental Constants ◽  
Future Prospects ◽  
Big Bang Nucleosynthesis ◽  
The Universe

Current theories that seek to unify gravity with the other fundamental interactions suggest that spatial and temporal variation of fundamental constants is a possibility, or even a necessity, in an expanding Universe. Several studies have tried to probe the values of constants at earlier stages in the evolution of the Universe, using tools such as big-bang nucleosynthesis, the Oklo natural nuclear reactor, quasar absorption spectra, and atomic clocks (see, e.g. Flambaum & Berengut (2009)).

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