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

TL;DR

This paper investigates the thermodynamic properties of Elko fermionic fields, proposing they can account for dark matter halos around galaxies through their degeneracy pressure at low temperatures.

Contribution

It calculates the partition function for Elko fields, showing their potential to explain dark matter halos without requiring new particles beyond Elko fermions.

Findings

Degeneracy pressure from Elko particles can form galaxy-sized dark matter halos.

Total dark matter mass from Elko particles matches typical galaxy masses.

Partition function for Elko matches that of Dirac fermions despite different equations.

Abstract

This work study 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 fermion 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 $0.1$eV and a density of just 0.1 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.