DARK GEOMETRY

2004 ◽  
Vol 13 (10) ◽  
pp. 2275-2279 ◽  
Author(s):  
J. A. R. CEMBRANOS ◽  
A. DOBADO ◽  
A. L. MAROTO
Keyword(s):  
Dark Matter ◽  
Extra Dimensions ◽  
Degrees Of Freedom ◽  
Planck Scale ◽  
Point Of View ◽  
Missing Mass ◽  
Brane Worlds ◽  
Mass Problem ◽  
Extra Space ◽  
The Universe

Extra-dimensional theories contain additional degrees of freedom related to the geometry of the extra space which can be interpreted as new particles. Such theories allow to reformulate most of the fundamental problems of physics from a completely different point of view. In this essay, we concentrate on the brane fluctuations which are present in brane-worlds, and how such oscillations of the own space–time geometry along curved extra dimensions can help to resolve the Universe missing mass problem. The energy scales involved in these models are low compared to the Planck scale, and this means that some of the brane fluctuations distinctive signals could be detected in future colliders and in direct or indirect dark matter searches.

THREE GENERATIONS: A PREDICTION FULFILLED

1990 ◽  
Vol 05 (09) ◽  
pp. 645-651
Author(s):  
JORGE L. LOPEZ ◽  
D.V. NANOPOULOS
Keyword(s):  
Dark Matter ◽  
Strong Correlation ◽  
Planck Scale ◽  
New Physics ◽  
Supersymmetric Particle ◽  
Three Generations ◽  
Unified Theories ◽  
The Universe

We recall the theoretical arguments that led us more than ten years ago to predict that there are only three generations. Quark-lepton mass relations (mb/mτ ≈ 2.8), as universally come out from unified theories at superhigh energies (close to the Planck scale), are the key point. We further argue that fractional deviations from Nν=3 may signal new physics. The supersymmetric decay Z→ÑÑ, with Ñ the lightest neutralino and lightest supersymmetric particle (LSP), easily fits the bill. In the specific case of flipped (SU(5)×U(1)) unification, there is a strong correlation between mt≈ O(90 ± 10) GeV, slepton masses of O(50 GeV) and the closure of the Universe due to Ñ dark matter, while ΔNν ≈ (0.1–0.5).

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,…).

The dynamics of galaxies and the 'missing mass' problem

1980 ◽  
Vol 296 (1419) ◽  
pp. 313-318 ◽  
Keyword(s):  
Dark Matter ◽  
Rotation Curve ◽  
Simple Theory ◽  
Missing Mass ◽  
Mass Problem ◽  
The Galaxy ◽  
Dynamics Of Galaxies ◽  
New Evidence

I review the observational situation concerning the existence of dark matter in the outer parts of galaxies. Observation now leaves little doubt of its presence, and both observation and simple theory suggest that the dark matter is probably bound to galaxies, and furthermore is present around both spirals and ellipticals. New evidence concerning the rotation curve of the Galaxy shows that the distribution of the halo stuff in our own system is roughly spherical, as seems natural from existing dynamical data on the nature of the halo material.

scholarly journals STRATEGIES TO LINK TINY NEUTRINO MASSES WITH HUGE MISSING MASS OF THE UNIVERSE

2011 ◽  
Vol 26 (15) ◽  
pp. 2461-2485 ◽  
Author(s):  
Y. FARZAN
Keyword(s):  
Dark Matter ◽  
Neutrino Mass ◽  
Rare Decays ◽  
Neutrino Masses ◽  
Kaon Decay ◽  
Electroweak Scale ◽  
Missing Mass ◽  
Lepton Flavor ◽  
Scale Models ◽  
The Universe

With the start of the LHC, interest in electroweak scale models for the neutrino mass has grown. In this paper, we review two specific models that simultaneously explain neutrino masses and provide a suitable DM candidate. We discuss the implications of these models for various observations and experiments including the LHC, Lepton Flavor Violating (LFV) rare decays, direct and indirect dark matter searches and kaon decay.

scholarly journals ACCELERATION OF THE UNIVERSE IN TYPE-0 NONCRITICAL STRINGS

2002 ◽  
Vol 17 (30) ◽  
pp. 4567-4589 ◽  
Author(s):  
G. A. DIAMANDIS ◽  
B. C. GEORGALAS ◽  
N. E. MAVROMATOS ◽  
E. PAPANTONOPOULOS
Keyword(s):  
String Theory ◽  
Extra Dimensions ◽  
Scattering Matrix ◽  
Relative Magnitude ◽  
Observational Evidence ◽  
De Sitter ◽  
Brane Worlds ◽  
Acceleration Of The Universe ◽  
Noncritical Strings ◽  
The Universe

Presently there is preliminary observational evidence that the cosmological constant might be nonzero, and hence that our universe is eternally accelerating (de Sitter). This poses fundamental problems for string theory, since a scattering matrix is not well defined in such universes. In a previous paper we have presented a model, based on (nonequilibrium) noncritical strings, which is characterized by eventual "graceful" exit from a de Sitter phase. The model is based on a type-0 string theory, involving D3 brane worlds, whose initial quantum fluctuations induce the noncriticality. We argue in this paper that this model is compatible with the current observations. A crucial role for the correct "phenomenology" of the model is played by the relative magnitude of the flux of the five-form of the type 0 string to the size of five of the extra dimensions, transverse to the direction of the flux-field. We do not claim, at this stage at least, that this model is a realistic physical model for the universe, but we find it interesting that the model cannot be ruled out immediately, at least on phenomenological grounds.

scholarly journals The ‘Missing Mass Problem’ in Astronomy and the Need for a Modified Law of Gravity

2014 ◽  
Vol 69 (3-4) ◽  
pp. 173-187 ◽  
Author(s):  
Sascha Trippe
Keyword(s):  
Dark Matter ◽  
Stellar Dynamics ◽  
Stellar Systems ◽  
Gravitational Acceleration ◽  
Missing Mass ◽  
Astronomical Observations ◽  
Groups Of Galaxies ◽  
Mass Problem ◽  
Multiple Observations ◽  
Law Of Gravity

Since the 1930s, astronomical observations have accumulated evidence that our understanding of the dynamics of galaxies and groups of galaxies is grossly incomplete: assuming the validity of Newton’s law of gravity on astronomical scales, the observed mass (stored in stars and interstellar gas) of stellar systems can account only for roughly 10% of the dynamical (gravitating) mass required to explain the high velocities of stars in those systems. The standard approach to this ‘missing mass problem’ has been the postulate of ‘dark matter’, meaning an additional, electromagnetically dark, matter component that provides the missing mass. However, direct observational evidence for dark matter has not been found to date. More importantly, astronomical observations obtained during the last decade indicate that dark matter cannot explain the kinematics of galaxies. Multiple observations show that the discrepancy between observed and dynamical mass is a function of gravitational acceleration (or field strength) but not of other parameters (size, rotation speed, etc.) of a galaxy; the mass discrepancy appears below a characteristic and universal acceleration aM = (1:1±0:1) · 10-10 ms-2 (Milgrom’s constant). Consequently, the idea of a modified law of gravity, specifically the ansatz of modified Newtonian dynamics (MOND), is becoming increasingly important in astrophysics. MOND has successfully predicted various important empirical relations of galaxy dynamics, including the famous Tully-Fisher and Faber-Jackson relations. MOND is found to be consistent with stellar dynamics from binary stars to clusters of galaxies, thus covering stellar systems spanning eight orders of magnitude in size and 14 orders of magnitude in mass. These developments have the potential to initiate a paradigm shift from dark matter to a modified law of gravity as the physical mechanism behind the missing mass problem.

scholarly journals Nearly Supersymmetric Dark Atoms

2011 ◽  
Vol 2011 ◽  
pp. 1-34 ◽  
Author(s):  
Siavosh R. Behbahani ◽  
Martin Jankowiak ◽  
Tomas Rube ◽  
Jay G. Wacker
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Supersymmetry Breaking ◽  
Bound States ◽  
Dark Sector ◽  
Missing Mass ◽  
The Standard Model ◽  
The Universe

Theories of dark matter that support bound states are an intriguing possibility for the identity of the missing mass of the Universe. This article proposes a class of models of supersymmetric composite dark matter where the interactions with the Standard Model communicate supersymmetry breaking to the dark sector. In these models, supersymmetry breaking can be treated as a perturbation on the spectrum of bound states. Using a general formalism, the spectrum with leading supersymmetry effects is computed without specifying the details of the binding dynamics. The interactions of the composite states with the Standard Model are computed, and several benchmark models are described. General features of nonrelativistic supersymmetric bound states are emphasized.

scholarly journals Some Regularities in the Missing Mass Problem

1987 ◽  
Vol 117 ◽  
pp. 136-136
Author(s):  
S. Casertano ◽  
J. N. Bahcall
Keyword(s):  
Dark Matter ◽  
Rotation Curve ◽  
Full Description ◽  
Mass Model ◽  
Missing Mass ◽  
Mass Problem ◽  
Available Information ◽  
Optical Radius

We discuss available information on the distribution of luminous and dark matter in eight galaxies. The galaxies have been chosen according to the following criteria: 1) existence of a good rotation curve, extending well beyond the optical radius; 2) a mass model has been published; 3) valuable constraints can be put on the amount of dark matter inside the optical radius. A full description of the data and reduction procedures is in Bahcall and Casertano (1985).

A Clifford-gravity-based cosmology, dark matter and dark energy

2015 ◽  
Vol 12 (03) ◽  
pp. 1550037 ◽  
Author(s):  
Carlos Castro
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Degrees Of Freedom ◽  
Vacuum Energy ◽  
Vacuum Energy Density ◽  
De Sitter ◽  
Four Dimensions ◽  
Accelerating Expansion ◽  
Expansion Of The Universe ◽  
The Universe

A Clifford-gravity-based model is exploited to build a generalized action (beyond the current ones used in the literature) and arrive at relevant numerical results which are consistent with the presently-observed de Sitter accelerating expansion of the universe driven by a very small vacuum energy density ρ obs ~ 10-120(MP)4 (MP is the Planck mass) and provide promising dark energy/matter candidates in terms of the 16 scalars corresponding to the degrees of freedom associated with a Cl (3, 1)-algebra-valued scalar field Φ in four dimensions.

scholarly journals Inverse Seesaw, dark matter and the Hubble tension

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
E. Fernandez-Martinez ◽  
M. Pierre ◽  
E. Pinsard ◽  
S. Rosauro-Alcaraz
Keyword(s):  
Dark Matter ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Degrees Of Freedom ◽  
Lepton Number ◽  
Neutrino Masses ◽  
Sterile Neutrinos ◽  
Seesaw Mechanism ◽  
The Universe ◽  
Matter Component

AbstractWe consider the inverse Seesaw scenario for neutrino masses with the approximate Lepton number symmetry broken dynamically by a scalar with Lepton number two. We show that the Majoron associated to the spontaneous symmetry breaking can alleviate the Hubble tension through its contribution to $$\Delta N_\text {eff}$$ Δ N eff and late decays to neutrinos. Among the additional fermionic states required for realizing the inverse Seesaw mechanism, sterile neutrinos at the keV-MeV scale can account for all the dark matter component of the Universe if produced via freeze-in from the decays of heavier degrees of freedom.

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