Long-Range Interactions Between Dark-Matter Particles in a Model With a Cosmological, Spontaneously-Broken Chiral Symmetry

Abstract

In a cosmological model with a chiral symmetry, there are two, dynamicallyrelated spin-zero fields, a scalar φ and a pseudoscalar b. These fields have self-interactions. Spontaneous symmetry breaking results in a very massive scalar particle with m φ ∼ = 5×10 11 GeV, and a nearly massless, (Goldstonelike) pseudoscalar particle with 0 < m b < ∼ 2.7×10 −6 eV. One or both particles can be part of dark matter. There are coherent long-range interactions (at range ∼ 1/m b > ∼ 10 cm), from exchange of a b particle between a pair of b particles, a pair of φ particles, and between a φ and a b. We compare the strength of potentials for the different pairs to the corresponding gravitational potentials (within the same range ∼ 1/m b ), and show that the new force dominates between a b pair, that gravitation dominates between a φ pair, and that the potentials are comparable for a φ-b pair. The new interaction strength between a b pair is comparable to the gravitational interaction between a φ pair; its possibly greater coherent effect originates in the possibility that the number density of a very light b can be greater than that of a massive φ. We consider these results in the context of recent speculations concerning possible effects of special forces between dark-matter particles on certain galactic, and inter-galactic, properties.In this note, we point out the strength, and certain possible physical consequences, of coherent long-range interactions which can exist only between darkmatter particles. These interactions arise naturally in a model with a cosmological, spontaneously-broken chiral symmetry [1,2]. There have been a number of speculations about such forces. For example, one motivation [3] has been to 1

Constraining Interactions in Cosmology's Dark Sector

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Interaction of neutrinos with a cosmological k-essence scalar

“…It is evident from (12) that the curvature scalar acts as a mass term. However, as we discussed earlier, in most k-essence models higher derivatives of the field φ will be negligible, and therefore we can ignore R from here on out.…”

“…If there is a scalar field pervading the universe then the effective field theory viewpoint implies that it must undergo interactions with the matter that is present. The question of the observabilty of dark energy directly through its couplings to ordinary matter is an important one [6,7,8,9,10,11,12,13,14,15,16,17] and this paper attempts to address aspects of it in the context of k-essence. On short distance scales the universe is inhomogenous with, in particular, plenty of black holes.…”

Dark-Matter Particles and Baryons From Inflation and Spontaneous Cp Violation in the Early Universe

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“…This could further ensure dark-matter smoothness. [12] F 10 Only small fluctuations in the radiation temperature are induced (see Appendix). This suggests that fluctuations may become smaller at the largest angular scales (the largest dimensions).…”