Is the current estimation of the ratio of dark matter to visible matter the result of a simple miscalculation?

2012 ◽  
Vol 25 (3) ◽  
pp. 306-314
Author(s):  
Donald Cameron
Keyword(s):  
Dark Matter ◽  
Current Estimation ◽  
Visible Matter

The first results of PandaX-4T

2022 ◽  
Author(s):  
Jianglai Liu
Keyword(s):  
Dark Matter ◽  
Data Analysis ◽  
Liquid Xenon ◽  
Observable Universe ◽  
Fundamental Particle ◽  
Search Results ◽  
Visible Matter ◽  
First Results ◽  
New Type ◽  
Deep Underground

Dark matter, an invisible substance which constitutes 85% of the matter in the observable universe, is one of the greatest puzzles in physics and astronomy today. Dark matter can be made of a new type of fundamental particle, not yet observed due to its feeble interactions with visible matter. In this talk, we present the first results of PandaX-4T, a 4-ton-scale liquid xenon dark matter observatory, searching for these dark matter particles from deep underground. We will briefly summarize the performance of PandaX-4T, introduces details in the data analysis, and present the latest search results on dark matter-nucleon interactions.

Dark matter distribution in superthin galaxies

2020 ◽  
Vol 495 (4) ◽  
pp. 3722-3726
Author(s):  
Ilia Kalashnikov
Keyword(s):  
Dark Matter ◽  
Surface Density ◽  
Distribution Density ◽  
Spherically Symmetric ◽  
Matter Distribution ◽  
Galactic Disc ◽  
Density Profiles ◽  
Visible Matter ◽  
Simple Physical Model ◽  
Dark Matter Distribution

ABSTRACT This paper presents a new method of calculating dark matter density profiles for superthin axial symmetric galaxies without a bulge. This method is based on a simple physical model, which includes an infinitely thin galactic disc immersed in a spherically symmetric halo of dark matter. To obtain the desired distribution density, it suffices to know a distribution of visible matter surface density in a galaxy and a dependence of angular velocity on the radius. As a byproduct, the well-known expression, which reproduces surface density of a superthin galaxy expressed through a rotation law, was obtained.

scholarly journals Constraining the interaction strength between dark matter and visible matter: I. Fermionic dark matter

2012 ◽  
Vol 854 (2) ◽  
pp. 350-374 ◽  
Author(s):  
Jia-Ming Zheng ◽  
Zhao-Huan Yu ◽  
Jun-Wen Shao ◽  
Xiao-Jun Bi ◽  
Zhibing Li ◽  
...  
Keyword(s):  
Dark Matter ◽  
Interaction Strength ◽  
Visible Matter

scholarly journals The visible matter – dark matter coupling

2004 ◽  
Vol 220 ◽  
pp. 233-240 ◽  
Author(s):  
Renzo Sancisi
Keyword(s):  
Dark Matter ◽  
Rotation Curve ◽  
Close Correlation ◽  
Stellar Disk ◽  
Strongly Correlated ◽  
Close Coupling ◽  
Visible Matter ◽  
Low Surface Brightness ◽  
Central Regions ◽  
Inner Parts

In the inner parts of spiral galaxies, of high or low surface brightness, there is a close correlation between rotation curve shape and light distribution. For any feature in the luminosity profile there is a corresponding feature in the rotation curve and vice versa. This implies that the gravitational potential is strongly correlated with the distribution of luminosity: either the luminous mass dominates or there is a close coupling between luminous and dark matter. in a similar way, the declining rotation curves observed in the outer parts of high luminosity systems are a clear signature of the stellar disk which either dominates or traces the distribution of mass.The notion that the baryons are dynamically important in the centres of galaxies, including LSBs, undermines the whole controversy over the cusps in CDM halos and the comparison with the observations. If the baryons dominate in the central regions of all spirals, including LSBs, how can the CDM profiles be compared with the observations? Alternatively, if the baryons do not dominate but simply trace the DM distribution, why, in systems of comparable luminosity, are some DM halos cuspy (like the light) and others (also like the light) are not?

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.

scholarly journals Alternatives to Dark Matter (?)

2004 ◽  
Vol 220 ◽  
pp. 17-26 ◽  
Author(s):  
Anthony Aguirre
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
General Idea ◽  
Galactic Dynamics ◽  
Modified Newtonian Dynamics ◽  
Newtonian Dynamics ◽  
Visible Matter

It has long been known that Newtonian dynamics applied to the visible matter in galaxies and clusters does not correctly describe the dynamics of those systems. While this is generally taken as evidence for dark matter it is in principle possible that instead Newtonian dynamics (and with it General Relativity) breaks down in these systems. Indeed there have been a number of proposals as to how standard gravitational dynamics might be modified so as to correctly explain galactic dynamics without dark matter. I will review this general idea (but focus on “MOdified Newtonian Dynamics”, or “MOND”), and discuss a number of ways alternatives to dark matter can be tested and, in many cases, ruled out.

Is There a Fifth-Force? Using Galaxy Mergers to Constrain Dark-Matter Self-Interactions

2017 ◽  
Author(s):  
Maggie McLean
Keyword(s):  
Dark Matter ◽  
Numerical Simulations ◽  
Fundamental Problem ◽  
Interacting Galaxies ◽  
Galaxy Mergers ◽  
Tidal Disruption ◽  
Fifth Force ◽  
Tidal Forces ◽  
Visible Matter ◽  
The Universe

Over ninety percent of the matter in the universe is believed to be “dark matter,” a mysterious form of matter the nature of which is still unknown. Since it cannot be detected directly, dark matter can only be inferred from its effect on visible matter. This leaves a significant gap in our knowledge. Without the ability to measure the influence of dark matter on other dark matter, we could miss a possible fifth fundamental force which mediates dark matter self-interactions. We propose a means of constraining the existence of a “fifth-force” by observing galaxies that are in the process of merging. Using numerical simulations, we examine the effect of including a hypothetical fifth-force on the tidal disruption of visible matter during galaxy mergers. We find distinct differences in the formation and appearance of tidal features produced during these interactions, providing an observable constraint on the strength of any “fifth-force.” The sheer volume of interacting galaxies that can be observed makes tidal forces a valuable tool in studying a fundamental problem that would otherwise pose a great challenge for physicists.

Evaluation of Bianchi type VI0 magnetized anisotropic dark energy models with constant deceleration parameter in bimetric theory of gravitation

2015 ◽  
Vol 24 (02) ◽  
pp. 1550019 ◽  
Author(s):  
M. S. Borkar ◽  
A. Ameen
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Bianchi Type ◽  
Constant Deceleration Parameter ◽  
Exponential Law ◽  
Anisotropic Dark Energy ◽  
Energy Models ◽  
Visible Matter ◽  
Theory Of Gravitation ◽  
The Universe

In this paper, Bianchi type VI0 magnetized anisotropic dark energy models with constant deceleration parameter have been studied by solving the Rosen's field equations in Bimetric theory of gravitation. The models corresponding to power law expansion and exponential law expansion have been evaluated and studied their nature geometrically and physically. It is seen that there is real visible matter (baryonic matter) suddenly appeared only for small interval of time 0.7 ≤ t < 0.7598 and for the remaining whole range of time t, there is dark energy matter in the universe. Our investigations are supported to the observational fact that the usual matter described by known particle theory is about 4% and the dark energy cause the accelerating expansion of the universe and several high precision observational experiments, especially the Wilkinson Microwave Anisotropic Probe (WMAP) satellite experiment (see [C. L. Bennett et al., Astrophys. J. Suppl. Ser. 148 (2003) 1; WMAP Collab. (D. N. Spergel et al.), Astrophys. J. Suppl. Ser. 148 (2003) 175; D. N. Spergel et al., Astrophys. J. Suppl. 170 (2007) 377; WMAP Collab. (E. Komastu et al.), Astrophys. J. Suppl. 180 (2009) 330; WMAP Collab. (G. Hinshaw et al.), Astrophys. J. Suppl. 208 (2013) 19; Plank Collab. (P. A. R. Ade), arXiv:1303.5076; arXiv:1303.5082]) conclude that the dark energy occupies near about 73% of the energy of the universe and dark matter is about 23%. In exponential law of expansion, our model is fully occupied by real visible matter and there is no chance of dark energy and dark matter.

scholarly journals Unified Origin for Baryonic Visible Matter and Antibaryonic Dark Matter

2010 ◽  
Vol 105 (21) ◽  
Author(s):  
Hooman Davoudiasl ◽  
David E. Morrissey ◽  
Kris Sigurdson ◽  
Sean Tulin
Keyword(s):  
Dark Matter ◽  
Visible Matter
Sign in / Sign up

Export Citation Format

Share Document