scholarly journals Partition function for a mass dimension one fermionic field and the dark matter halo of galaxies

2019 ◽  
Vol 34 (16) ◽  
pp. 1950126 ◽  
Author(s):  
S. H. Pereira ◽  
Richard S. Costa
Keyword(s):  
Dark Matter ◽  
Partition Function ◽  
Pauli Exclusion Principle ◽  
Dark Matter Halo ◽  
Exclusion Principle ◽  
Galactic Halos ◽  
Fermionic Field ◽  
Time Formalism ◽  
Mass Dimension ◽  
Dimension One

This work studies the finite temperature effects of a mass dimension one fermionic field, sometimes called Elko field. The equilibrium partition function was calculated by means of the imaginary time formalism and the result obtained was the same for a Dirac fermionic field, even though the Elko field does not satisfy a Dirac-like equation. The high and low temperature limits were obtained, and for the last case the degeneracy pressure due to Pauli exclusion principle can be responsible for the dark matter halos around galaxies to be greater than or of the same order of the galaxy radius. Also, for a light particle of about 1.0 eV and a density of just 1 particle per cubic centimeter, the value of the total dark matter mass due to Elko particles is of the same order of a typical galaxy. Such a result satisfactorily explains the dark matter as being formed just by Elko fermionic particles and also the existence of galactic halos that go beyond the observable limit.

scholarly journals New mass bound on fermionic dark matter from a combined analysis of classical dSphs

2019 ◽  
Vol 487 (4) ◽  
pp. 5711-5720 ◽  
Author(s):  
D Savchenko ◽  
A Rudakovskyi
Keyword(s):  
Dark Matter ◽  
Lower Bound ◽  
Cold Dark Matter ◽  
Pauli Exclusion Principle ◽  
Dark Matter Halo ◽  
Exclusion Principle ◽  
Fermion Mass ◽  
Density Profiles ◽  
Combined Analysis ◽  
Dwarf Spheroidal Galaxies

ABSTRACTDwarf spheroidal galaxies (dSphs) are the most compact dark-matter-dominated objects observed so far. The Pauli exclusion principle limits the number of fermionic dark matter particles that can compose a dSph halo. This results in a well-known lower bound on their particle mass. So far, such bounds were obtained from the analysis of individual dSphs. In this paper, we model dark matter halo density profiles via the semi-analytical approach and analyse the data from eight ‘classical’ dSphs assuming the same mass of dark matter fermion in each object. First, we find out that modelling of Carina dSph results in a much worse fitting quality compared to the other seven objects. From the combined analysis of the kinematic data of the remaining seven ‘classical’ dSphs, we obtain a new 2σ lower bound of m ≳ 190 eV on the dark matter fermion mass. In addition, by combining a sub-sample of four dSphs – Draco, Fornax, Leo I, and Sculptor – we conclude that 220 eV fermionic dark matter appears to be preferred over the standard cold dark matter at about the 2σ level. However, this result becomes insignificant if all seven objects are included in the analysis. Future improvement of the obtained bound requires more detailed data, both from ‘classical’ and ultra-faint dSphs.

scholarly journals A new class of mass dimension one fermions

2020 ◽  
Vol 476 (2240) ◽  
pp. 20200249 ◽  
Author(s):  
Dharam Vir Ahluwalia
Keyword(s):  
Dark Matter ◽  
Field Energy ◽  
First Principle ◽  
Square Root ◽  
Identity Matrix ◽  
Quantum Fields ◽  
Fermionic Field ◽  
New Class ◽  
Mass Dimension ◽  
Dimension One

These are notes on the square root of a 4 × 4 identity matrix and associated quantum fields of spin one half. The method is illustrated by constructing a new mass dimension one fermionic field. The presented field is local. The field energy is bounded from below. It is argued that these fermions are a first-principle candidate for dark matter with an unsuppressed quartic self-interaction.

scholarly journals Structure of Dark Matter Halo

1999 ◽  
Vol 183 ◽  
pp. 155-155
Author(s):  
Toshiyuki Fukushige ◽  
Junichiro Makino
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Temperature Inversion ◽  
Dark Matter Halo ◽  
Temperature Structure ◽  
Galactic Halos ◽  
Dark Matter Halos ◽  
Density Profiles ◽  
Order Of Magnitude ◽  
Special Purpose Computer

We performed N-body simulation on special-purpose computer, GRAPE-4, to investigate the structure of dark matter halos (Fukushige, T. and Makino, J. 1997, ApJL, 477, L9). Universal profile proposed by Navarro, Frenk, and White (1996, ApJ, 462, 563), which has cusp with density profiles ρ ∝r−1in density profile, cannot be reproduced in the standard Cold Dark Matter (CDM) picture of hierarchical clustering. Previous claims to the contrary were based on simulations with relatively few particles, and substantial softening. We performed simulations with particle numbers an order of magnitude higher, and essentially no softening, and found that typical central density profiles are clearly steeper than ρ ∝r−1, as shown in Figure 1. In addition, we confirm the presence of a temperature inversion in the inner 5 kpc of massive galactic halos, and give a natural explanation for formation of the temperature structure.

scholarly journals New Limits on Bosonic Dark Matter, Solar Axions, Pauli Exclusion Principle Violation, and Electron Decay from the Majorana Demonstrator

2017 ◽  
Vol 118 (16) ◽  
Author(s):  
N. Abgrall ◽  
I. J. Arnquist ◽  
F. T. Avignone ◽  
A. S. Barabash ◽  
F. E. Bertrand ◽  
...  
Keyword(s):  
Dark Matter ◽  
Pauli Exclusion Principle ◽  
Exclusion Principle ◽  
Solar Axions

On the thermal conductivity in dense stars

1950 ◽  
Vol 46 (2) ◽  
pp. 331-338 ◽  
Author(s):  
L. Mestel
Keyword(s):  
Thermal Conductivity ◽  
Partition Function ◽  
Pauli Exclusion Principle ◽  
Exclusion Principle ◽  
Series Expansions ◽  
Boltzmann Gas ◽  
Dense Stars ◽  
Degeneracy Parameter ◽  
Physical Quantities ◽  
Numerical Quadratures

In considering the equilibrium of stars of high density the effects of the Pauli Exclusion Principle must be taken into account. For large values of the degeneracy parameter, which will be denoted by λ, an explicit formula for the partition function may be obtained, from which we may easily find the pressure and density in terms of λ. When λ ≪ 1 the relations for a Fermi-Dirac gas reduce to those for a Boltzmann gas. For λ of the order of, but less than, unity, series expansions for the relevant physical quantities can be found, but for λ of the order of, but greater than, unity, a set of numerical quadratures must be performed at intervals (in λ) close enough for interpolation purposes. The method for this is discussed in § 2 and the numerical results are given at the end of the paper.

scholarly journals Dark matter: A spin one-half fermion field with mass dimension one?

2005 ◽  
Vol 72 (6) ◽  
Author(s):  
D. V. Ahluwalia-Khalilova ◽  
D. Grumiller
Keyword(s):  
Dark Matter ◽  
Fermion Field ◽  
Mass Dimension ◽  
Dimension One

scholarly journals Searching for Elko dark matter spinors at the CERN LHC

2015 ◽  
Vol 30 (01) ◽  
pp. 1550006 ◽  
Author(s):  
Alexandre Alves ◽  
F. de Campos ◽  
M. Dias ◽  
J. M. Hoff da Silva
Keyword(s):  
Dark Matter ◽  
Hadron Collider ◽  
Higgs Field ◽  
Tree Level ◽  
Dark Matter Candidate ◽  
Mass Dimension ◽  
Quartic Interaction ◽  
Relic Abundance ◽  
Dimension One ◽  
Higgs Portal

The aim of this paper is to explore the possibility of discovering a fermionic field with mass dimension one, the Elko field, in the Large Hadron Collider. Due to its mass dimension, an Elko can only interact either with Standard Model spinors and gauge fields at one-loop order or at tree level through a quartic interaction with the Higgs field. In this Higgs portal scenario, the Elko is a viable candidate to a dark matter constituent which has been shown to be compatible with relic abundance measurements from WMAP and direct dark matter searches. We propose a search strategy for this dark matter candidate in the channel [Formula: see text] at the [Formula: see text] LHC. We show the LHC potential to discover the Elko considering a triple Higgs–Elkos coupling as small as ~0.5 after 1 ab-1 of integrated luminosity. Some phenomenological consequences of this new particle and its collider signatures are also discussed.

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