scholarly journals Dark Matter Realism

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Niels C. M. Martens
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Logical Empiricism ◽  
Mass Energy ◽  
Current State ◽  
The Standard Model ◽  
Luminous Matter ◽  
History Of ◽  
The Universe ◽  
Current Stage

AbstractAccording to the standard model of cosmology, $$\Lambda $$ Λ CDM, the mass-energy budget of the current stage of the universe is not dominated by the luminous matter that we are familiar with, but instead by some form of dark matter (and dark energy). It is thus tempting to adopt scientific realism about dark matter. However, there are barely any constraints on the myriad of possible properties of this entity—it is not even certain that it is a form of matter. In light of this underdetermination I advocate caution: we should not (yet) be dark matter realists. The “not(-yet)-realism” that I have in mind is different from Hacking’s (Philos Sci 56 (4), 555–581, 1989) anti-realism, in that it is semantic rather than epistemological. It also differs from the semantic anti-realism of logical empiricism, in that it is naturalistic, such that it may only be temporary and does not automatically apply to all other unobservables (or even just to all other astronomical unobservables, as with Hacking’s anti-realism). The argument is illustrated with the analogy of the much longer history of the concept of a gene, as the current state of the concept of dark matter resembles in some relevant ways that of the early concept of genes.

scholarly journals Dark Matter and Dark Energy in the Universe

BIBECHANA ◽  
2014 ◽  
Vol 11 ◽  
pp. 8-16 ◽  
Author(s):  
BC Paul
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Particle Physics ◽  
Late Phase ◽  
Exponential Phase ◽  
Astronomical Observations ◽  
The Standard Model ◽  
Present Universe ◽  
The Universe

Cosmological and astronomical observations predict that the present Universe is passing through an accelerating phase of expansion. The Universe emerged out of an exponential phase in the very early Universe. The scalar field of the standard model of particle physics when used in cosmology admits such a phase of expansion known as inflation. The most favourable condition for inflation with scalar field to admit an Inflationary scenario is that the potential energy must dominate over the kinetic energy which one obtains with a flat potential. Thereafter the Universe enters into a matter dominated phase when the field oscillates at the minimum of the potential. But it is not possible to accommodate the present accelerating phase in the Einstein’s gravity. It is known from observational analysis that about 73 % matter is responsible for the late phase expansion and 23 % matter called Dark Matter is responsible for a stable galaxy. We discuss here the relevant fields and theories that are useful for describing the late Universe. DOI: http://dx.doi.org/10.3126/bibechana.v11i0.10374 BIBECHANA 11(1) (2014) 8-16

scholarly journals Pendidikan Ilmu Astronomi Dari Historis Sampai Heliosentris

2018 ◽  
Vol 2 (2) ◽  
pp. 93-110
Author(s):  
Nabil Nabil
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Dark Energy ◽  
Human Life ◽  
History Of Astronomy ◽  
The West ◽  
History Of ◽  
The Creation ◽  
The Universe ◽  
Origin Of The Universe

Science in human life is very important to illuminate every walk of life, both physical (material) and metaphysical (immaterial). The universe was born millions and even billions of years ago, so many astronomical physicists calculate the origin of the universe, so the creation of the theory of bigbang, black holes, dark energy, dark matter, newton gravity, etc. Astronomy is important in teaching to know the phenomena of the universe (general), and to know times of worship (specifically). Before entering the science, it is better to know the history of astronomy, both the history of theory, and the figures then the hierarchy between geocentric and heliocentric in several views, both from the view of a character, as well as the view of the scriptures. Indeed, when humans think about the universe, in this case about the center of the universe there will be a hierarchy with the scriptures. This is a matter between different reason and revelation. Therefore, in this paper I touch on the issue of Heliocentric and Geocentric. And do not forget the astronomical figures from the West and East.

Today’s Standard Models of Particles and Gravity

2018 ◽  
pp. 129-131
Author(s):  
Alvaro De Rújula
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Energy Density ◽  
Quantum Gravity ◽  
Dark Energy Density ◽  
The Standard Model ◽  
Standard Models ◽  
Drawing Board ◽  
Hubble’S Law ◽  
The Universe

The missing particle of the standard model: the “axion.” Our considerable ignorance concerning dark matter and the dark energy density of the Universe. No decent theory of quantum gravity. How all this sends us back to the drawing board, and to return to observations of the Universe, starting with Hubble’s law of its expansion.

scholarly journals What if ALP dark matter for the XENON1T excess is the inflaton

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Fuminobu Takahashi ◽  
Masaki Yamada ◽  
Wen Yin
Keyword(s):  
Dark Matter ◽  
Early Universe ◽  
Decay Constant ◽  
The Standard Model ◽  
Electron Recoil ◽  
History Of ◽  
The Alps ◽  
The Right ◽  
The Universe

Abstract The recent XENON1T excess in the electron recoil data can be explained by anomaly-free axion-like particle (ALP) dark matter with mass mϕ = 2.3 ± 0.2 keV and the decay constant $$ {f}_{\phi }/{q}_e\simeq 2\times {10}^{10}\sqrt{\Omega_{\phi }/{\Omega}_{\mathrm{DM}}} $$ f ϕ / q e ≃ 2 × 10 10 Ω ϕ / Ω DM GeV. Intriguingly, the suggested mass and decay constant are consistent with the relation, $$ {f}_{\phi}\sim {10}^3\sqrt{m_{\phi }{M}_p} $$ f ϕ ∼ 10 3 m ϕ M p , predicted in a scenario where the ALP plays the role of the inflaton. This raises a possibility that the ALP dark matter responsible for the XENON1T excess also drove inflation in the very early universe. We study implications of the XENON1T excess for the ALP inflation and thermal history of the universe after inflation. We find that the successful reheating requires the ALP couplings to heavy fermions in the standard model, which results in an instantaneous reheating and subsequent thermalization of the ALPs. Then, an entropy dilution of $$ \mathcal{O} $$ O (10) is necessary to explain the XENON1T excess, which can be achieved by decays of the right-handed neutrinos.

scholarly journals Displaced new physics at colliders and the early universe before its first second

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Lorenzo Calibbi ◽  
Francesco D’Eramo ◽  
Sam Junius ◽  
Laura Lopez-Honorez ◽  
Alberto Mariotti
Keyword(s):  
Dark Matter ◽  
Early Universe ◽  
Upper Bound ◽  
New Physics ◽  
Early History ◽  
Relic Density ◽  
History Of ◽  
Indirect Information ◽  
The Universe

Abstract Displaced vertices at colliders, arising from the production and decay of long-lived particles, probe dark matter candidates produced via freeze-in. If one assumes a standard cosmological history, these decays happen inside the detector only if the dark matter is very light because of the relic density constraint. Here, we argue how displaced events could very well point to freeze-in within a non-standard early universe history. Focusing on the cosmology of inflationary reheating, we explore the interplay between the reheating temperature and collider signatures for minimal freeze-in scenarios. Observing displaced events at the LHC would allow to set an upper bound on the reheating temperature and, in general, to gather indirect information on the early history of the universe.

scholarly journals INTERACTION BETWEEN DARK ENERGY AND DARK MATTER: OBSERVATIONAL CONSTRAINTS FROM OHD, BAO, CMB AND SNe Ia

2013 ◽  
Vol 22 (14) ◽  
pp. 1350082 ◽  
Author(s):  
SHUO CAO ◽  
NAN LIANG
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Observational Constraints ◽  
Coincidence Problem ◽  
Cosmological Constraints ◽  
Coincidence Index ◽  
Acceleration Of The Universe ◽  
Interaction Term ◽  
Negative Coupling ◽  
The Universe

In order to test if there is energy transfer between dark energy (DE) and dark matter (DM), we investigate cosmological constraints on two forms of nontrivial interaction between the DM sector and the sector responsible for the acceleration of the universe, in light of the newly revised observations including OHD, CMB, BAO and SNe Ia. More precisely, we find the same tendencies for both phenomenological forms of the interaction term Q = 3γHρ, i.e. the parameter γ to be a small number, |γ| ≈ 10-2. However, concerning the sign of the interaction parameter, we observe that γ > 0 when the interaction between dark sectors is proportional to the energy density of dust matter, whereas the negative coupling (γ < 0) is preferred by observations when the interaction term is proportional to DE density. We further discuss two possible explanations to this incompatibility and apply a quantitative criteria to judge the severity of the coincidence problem. Results suggest that the γm IDE model with a positive coupling may alleviate the coincidence problem, since its coincidence index C is smaller than that for the γd IDE model, the interacting quintessence and phantom models by four orders of magnitude.

scholarly journals A dark clue to seesaw and leptogenesis in a pseudo-Dirac singlet doublet scenario with (non)standard cosmology

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Partha Konar ◽  
Ananya Mukherjee ◽  
Abhijit Kumar Saha ◽  
Sudipta Show
Keyword(s):  
Dark Matter ◽  
Thermal History ◽  
Direct Detection ◽  
Critical Role ◽  
Mass Term ◽  
Baryon Asymmetry ◽  
Dark Sector ◽  
Lepton Asymmetry ◽  
History Of ◽  
The Universe

Abstract We propose an appealing alternative scenario of leptogenesis assisted by dark sector which leads to the baryon asymmetry of the Universe satisfying all theoretical and experimental constraints. The dark sector carries a non minimal set up of singlet doublet fermionic dark matter extended with copies of a real singlet scalar field. A small Majorana mass term for the singlet dark fermion, in addition to the typical Dirac term, provides the more favourable dark matter of pseudo-Dirac type, capable of escaping the direct search. Such a construction also offers a formidable scope to radiative generation of active neutrino masses. In the presence of a (non)standard thermal history of the Universe, we perform the detailed dark matter phenomenology adopting the suitable benchmark scenarios, consistent with direct detection and neutrino oscillations data. Besides, we have demonstrated that the singlet scalars can go through CP-violating out of equilibrium decay, producing an ample amount of lepton asymmetry. Such an asymmetry then gets converted into the observed baryon asymmetry of the Universe through the non-perturbative sphaleron processes owing to the presence of the alternative cosmological background considered here. Unconventional thermal history of the Universe can thus aspire to lend a critical role both in the context of dark matter as well as in realizing baryogenesis.

scholarly journals On The Symmetry of The Universe

2020 ◽  
Author(s):  
Engel Roza
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Thermodynamic Equilibrium ◽  
Vacuum Energy ◽  
Quantum Mechanical ◽  
Baryonic Matter ◽  
Time Uncertainty ◽  
Matter Effect ◽  
Mechanical Interpretation ◽  
The Universe

It is shown that the Lambda component in the cosmological Lambda-CDM model can be conceived as vacuum energy, consisting of gravitational particles subject to Heisenberg&rsquo;s energy-time uncertainty. These particles can be modelled as elementary polarisable Dirac-type dipoles (&ldquo;darks&rdquo;) in a fluidal space at thermodynamic equilibrium, with spins that are subject to the Bekenstein-Hawking entropy. Around the baryonic kernels, uniformly distributed in the universe, the spins are polarized, thereby invoking an increase of the effective gravitational strength of the kernels. It explains the dark matter effect to the extent that the numerical value of Milgrom&rsquo;s acceleration constant can be assessed by theory. Non-polarized vacuum particles beyond the baryonic kernels compose the dark energy. The result is a quantum mechanical interpretation of gravity in terms of quantitatively established shares in baryonic matter, dark matter and dark energy, which correspond with the values of the Lambda-CDM model..

scholarly journals The Search for Feebly Interacting Particles

2021 ◽  
Vol 71 (1) ◽  
pp. 279-313
Author(s):  
Gaia Lanfranchi ◽  
Maxim Pospelov ◽  
Philip Schuster
Keyword(s):  
Dark Matter ◽  
Particle Physics ◽  
Interaction Strength ◽  
New Physics ◽  
Fine Tuning ◽  
Experimental Program ◽  
Interacting Particles ◽  
Fundamental Physics ◽  
The Standard Model ◽  
The Universe

At the dawn of a new decade, particle physics faces the challenge of explaining the mystery of dark matter, the origin of matter over antimatter in the Universe, the apparent fine-tuning of the electroweak scale, and many other aspects of fundamental physics. Perhaps the most striking frontier to emerge in the search for answers involves New Physics at mass scales comparable to that of familiar matter—below the GeV scale but with very feeble interaction strength. New theoretical ideas to address dark matter and other fundamental questions predict such feebly interacting particles (FIPs) at these scales, and existing data may even provide hints of this possibility. Emboldened by the lessons of the LHC, a vibrant experimental program to discover such physics is underway, guided by a systematic theoretical approach that is firmly grounded in the underlying principles of the Standard Model. We give an overview of these efforts, their motivations, and the decadal goals that animate the community involved in the search for FIPs, and we focus in particular on accelerator-based experiments.

scholarly journals Dark Stars: Dark matter in the first stars leads to a new phase of stellar evolution

2008 ◽  
Vol 4 (S255) ◽  
pp. 56-60 ◽  
Author(s):  
Katherine Freese ◽  
Douglas Spolyar ◽  
Anthony Aguirre ◽  
Peter Bodenheimer ◽  
Paolo Gondolo ◽  
...  
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Cross Section ◽  
Stellar Evolution ◽  
Weakly Interacting Massive Particles ◽  
First Stars ◽  
History Of ◽  
Born Again ◽  
The Universe ◽  
New Phase

AbstractThe first phase of stellar evolution in the history of the universe may be Dark Stars, powered by dark matter heating rather than by fusion. Weakly interacting massive particles, which are their own antiparticles, can annihilate and provide an important heat source for the first stars in the the universe. This talk presents the story of these Dark Stars. We make predictions that the first stars are very massive (~800M⊙), cool (6000 K), bright (~106L⊙), long-lived (~106years), and probable precursors to (otherwise unexplained) supermassive black holes. Later, once the initial DM fuel runs out and fusion sets in, DM annihilation can predominate again if the scattering cross section is strong enough, so that a Dark Star is born again.

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