scholarly journals DES map shows a smoother distribution of matter than expected: a possible explanation

2021 ◽  
Vol 21 (10) ◽  
pp. 241
Author(s):  
Eugene Oks
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Beyond The Standard Model ◽  
Hydrogen Atoms ◽  
Standard Quantum ◽  
Dark Energy Survey ◽  
Multipole Radiation ◽  
Physical Laws ◽  
Energy Survey ◽  
The Universe

Abstract The largest and most detailed map of the distribution of dark matter in the Universe has been recently created by the Dark Energy Survey (DES) team. The distribution was found to be slightly (by a few percent) smoother and less clumpy than predicted by general relativity. This result was considered as a hint of some new physical laws. In the present paper we offer a relatively simple model that could explain the above result without resorting to any new physical laws. The model deals with the dynamics of a system consisting of a large number of gravitating neutral particles, whose mass is equal to the mass of hydrogen atoms. The central point of the model is a partial inhibition of the gravitation for a relatively small subsystem of the entire system. It would be sufficient for this subsystem to constitute just about a few percent of the total ensemble of particles for explaining the few percent more smooth distribution of dark matter (observed by the DES team) compared to the prediction of general relativity. The most viable candidate for the dark matter particles in this model is the second flavor of hydrogen atoms (SFHA) that has only S-states and therefore does not couple to the electric dipole radiation or even to higher multipole radiation, so that the SFHA is practically dark. The SFHA has experimental confirmation from atomic experiments, it does not go beyond the Standard Model, it is based on standard quantum mechanics and it explains puzzling astrophysical observations of the redshifted line 21 cm from the early Universe. Thus, our model explaining the DES result of a little too smooth distribution of dark matter without resorting to any new physical laws seems to be self-consistent.

scholarly journals Neutron stars as probes of dark matter

2020 ◽  
Vol 29 (14) ◽  
pp. 2043028
Author(s):  
M. Ángeles Pérez-García ◽  
Joseph Silk
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Equation Of State ◽  
Neutron Stars ◽  
Internal Structure ◽  
Stellar Objects ◽  
Ordinary Matter ◽  
Stable Solutions ◽  
The Universe

Neutron Stars (NSs) are compact stellar objects that are stable solutions in General Relativity. Their internal structure is usually described using an equation of state that involves the presence of ordinary matter and its interactions. However there is now a large consensus that an elusive sector of matter in the universe, described as dark matter, remains as yet undiscovered. In such a case, NSs should contain both, baryonic and dark matter. We argue that depending on the nature of the dark matter and in certain circumstances, the two matter components would form a mixture inside NSs that could trigger further changes, some of them observable. The very existence of NSs constrains the nature and interactions of dark matter in the universe.

scholarly journals Beyond the Standard Model at LEP

1991 ◽  
Vol 336 (1642) ◽  
pp. 247-259 ◽  
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Beyond The Standard Model ◽  
Grand Unified Theories ◽  
The Standard Model ◽  
Unified Theories ◽  
Massive Neutrinos ◽  
Supersymmetric Particles ◽  
The Universe

LEP data constrain severely many proposed extensions of the Standard Model. These include: massive neutrinos, which are now largely excluded as candidates for the dark matter of the Universe; supersymmetric particles, the lightest of which would still constitute detectable dark matter; technicolour, of which many favoured versions are now excluded by precision electroweak measurements; and grand unified theories, of which LEP data favour supersymmetric versions.

THE LHC AND THE UNIVERSE AT LARGE

2009 ◽  
Vol 24 (04) ◽  
pp. 657-669 ◽  
Author(s):  
PIERRE BINÉTRUY
Keyword(s):  
Phase Transition ◽  
Black Holes ◽  
Dark Matter ◽  
Extra Dimensions ◽  
Beyond The Standard Model ◽  
Electroweak Phase Transition ◽  
Primordial Gravitational Waves ◽  
The Standard Model ◽  
Particle Astrophysics ◽  
The Universe

I discuss here some of the deeper connections between the physics studied at the LHC (electroweak phase transition, physics beyond the Standard Model, extra dimensions) and some of the most important issues in the field of particle astrophysics and cosmology (dark matter, primordial gravitational waves, black holes,…).

scholarly journals Complex Limiting Velocity Expressions as Likely Characteristics of Dark Matter Particles

2020 ◽  
Vol 12 (4) ◽  
pp. 107
Author(s):  
Josip Soln
Keyword(s):  
Dark Matter ◽  
Particle Velocity ◽  
Dark Matter Particle ◽  
Model Description ◽  
Complex Conjugate ◽  
Beyond The Standard Model ◽  
Cosmological Observations ◽  
Angle Alpha ◽  
Limiting Velocity ◽  
The Universe

Many astrophysical and cosmological observations suggest that the matter in the universe is mostly of the dark matter type whose behavior goes beyond the Standard Model description. Hence it is justifiable to take a drastically different approach to the dark matter particles which is here done through the bicubic equation of limiting particle velocity formalism. The bicubic equation discriminant $D$ in this undertaking satisfy $D\succeq 0 $ determined by the congruent parameter $z$ satisfying $z^{2}\succeq 1$, where formally $z(m)=3\sqrt{3}mv^{2}/2E$, \ with $m$, $v$, and $E$ being respectively, particle mass, velocity and energy. Also nonlinearly related to the the particle congruent parameter $z$ is the particle congruent angle $% \alpha $ . These two dimensionless\ parameters $z$ \ and $\alpha $ simplify expressions in the bicubic equation limiting particle velocity formalism when evaluating the three particle limiting velocities, $c_{1},$ $c_{2}$\ and $c_{3},$ (primary, obscure and normal) in terms of the ordinary particle velocity, $v$. Corresponding to these limiting velocities \ one then deduces, with equal values, dark matter particle energies $E\left(c_{1}\right) $, $E\left( c_{2}\right) $ and $E\left( c_{3}\right) $. The exemplary values of the congruent parameters are in these regions, $1\preceq z\prec 3\sqrt{3}$ $/2$ and $\pi /2\succeq \alpha \succeq \pi /3$ . Already within these ranges of congruent parameters, the bicubic formalism yields for squares of particle limiting velocities that $c_{1}^{2}$ and $c_{2}^{2}$ are complex conjugate to each other, $c_{1}^{2\ast }=c_{2}^{2}$ ,and that $% c_{3\text{ }}^{2}$is real. The imaginary portions of $c_{1}^{2}$ and $% c_{2}^{2}$ do not change the realities of numerically equal to each other dark matter energies $E\left( c_{i}\right) ,i=1,2,3.$ In fact, real $E\left(c_{1,2}\right) $ energies can be equally evaluated with $c_{1,2}^{2}$ or $% \func{Re}$ $c_{1,2}^{2}$ or even with $\func{Im}c_{1,2}^{2}$ so that in new notation, $E\left( _{1,2}^{2}\right) =E\left( \func{Re}c_{1,2}^{2}\right) =E\left( \func{Im}c_{1,2}^{2}\right) $ $=E\left( c_{3}^{2}\right) $ all with the same real values. However, in these notations, the real particle momenta are $\overrightarrow{p}\left( (\func{Re}c_{1,2}^{2}\right) $ and $\\overrightarrow{p}\left( (c_{3}^{2}\right) $, defined with respective energies and, while in similar forms , numerically are different from each other.

Particle physics today, tomorrow and beyond

2018 ◽  
Vol 33 (02) ◽  
pp. 1830003 ◽  
Author(s):  
John Ellis
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Particle Physics ◽  
Beyond The Standard Model ◽  
Visible Matter ◽  
The Standard Model ◽  
Cosmological Inflation ◽  
The Stability ◽  
The Universe ◽  
Lhc I

The most important discovery in particle physics in recent years was that of the Higgs boson, and much effort is continuing to measure its properties, which agree obstinately with the Standard Model, so far. However, there are many reasons to expect physics beyond the Standard Model, motivated by the stability of the electroweak vacuum, the existence of dark matter and the origin of the visible matter in the Universe, neutrino physics, the hierarchy of mass scales in physics, cosmological inflation and the need for a quantum theory for gravity. Most of these issues are being addressed by the experiments during Run 2 of the LHC, and supersymmetry could help resolve many of them. In addition to the prospects for the LHC, I also review briefly those for direct searches for dark matter and possible future colliders.

Orbits

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Milky Way ◽  
Extrasolar Planets ◽  
Binary Star ◽  
Milky Way Galaxy ◽  
Newtonian Model ◽  
Theory Of Gravity ◽  
The Masses ◽  
The Universe

Orbits are ubiquitous in the universe: moons orbit planets, planets orbit stars, stars orbit around the center of the Milky Way galaxy, and so on. Any theory of gravity will have to explain the properties of all these orbits. To pave the way for developing the metric theory of gravity (general relativity) this chapter examines the basics of orbits as observed and as explained by the Newtonian model of gravity. We can use our understanding of gravity to infer the masses and other properties of these cosmic systems. Te chapter concludes with four optional sections in this spirit, covering the slingshot maneuver; dark matter; binary star orbits and how they reveal the masses of stars; and extrasolar planets.

scholarly journals The Milky Way’s total satellite population and constraining the mass of the warm dark matter particle

2018 ◽  
Vol 14 (S344) ◽  
pp. 109-113 ◽  
Author(s):  
Oliver Newton ◽  
Marius Cautun ◽  
Adrian Jenkins ◽  
Carlos S. Frenk ◽  
John C. Helly
Keyword(s):  
Dark Matter ◽  
Dark Matter Particle ◽  
Statistical Error ◽  
Sloan Digital Sky Survey ◽  
Dark Energy Survey ◽  
Satellite Galaxy ◽  
Sky Survey ◽  
Galaxy Luminosity Function ◽  
Energy Survey ◽  
Rule Out

AbstractThe Milky Way’s (MW) satellite population is a powerful probe of warm dark matter (WDM) models as the abundance of small substructures is very sensitive to the properties of the WDM particle. However, only a partial census of the MW’s complement of satellite galaxies exists because surveys of the MW’s close environs are incomplete both in depth and in sky coverage. We present a new Bayesian analysis that combines the sample of satellites recently discovered by the Dark Energy Survey (DES) with those found in the Sloan Digital Sky Survey (SDSS) to estimate the total satellite galaxy luminosity function down to Mv = 0. We find that there should be at least $124_{ - 27}^{ + 40}$ (68% CL, statistical error) satellites as bright or brighter than Mv = 0 within 300 kpc of the Sun, with only a weak dependence on MW halo mass. When it comes online the Large Synoptic Survey Telescope should detect approximately half of this population. We also show that WDM models infer the same number of satellites as in ΛCDM, which will allow us to rule out those models that produce insufficient substructure to be viable.

Dark matter (energy) may be indistinguishable from modified gravity (MOND)

2017 ◽  
Vol 26 (12) ◽  
pp. 1743010 ◽  
Author(s):  
C. Sivaram
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Dark Energy ◽  
Modified Gravity ◽  
Observational Evidence ◽  
Negative Results ◽  
Newtonian Dynamics ◽  
Special Cases ◽  
The Universe ◽  
Matter Energy

For Newtonian dynamics to hold over galactic scales, large amounts of dark matter (DM) are required which would dominate cosmic structures. Accounting for the strong observational evidence that the universe is accelerating requires the presence of an unknown dark energy (DE) component constituting about 70% of the matter. Several ingenious ongoing experiments to detect the DM particles have so far led to negative results. Moreover, the comparable proportions of the DM and DE at the present epoch appear unnatural and not predicted by any theory. For these reasons, alternative ideas like MOND and modification of gravity or general relativity over cosmic scales have been proposed. It is shown in this paper that these alternate ideas may not be easily distinguishable from the usual DM or DE hypotheses. Specific examples are given to illustrate this point that the modified theories are special cases of a generalized DM paradigm.

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