LONG-RANGE INTERACTIONS BETWEEN DARK-MATTER PARTICLES IN A MODEL WITH A COSMOLOGICAL, SPONTANEOUSLY-BROKEN CHIRAL SYMMETRY
In a cosmological model with a chiral symmetry, there are two, dynamically-related 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 mϕ≅5×1011 GeV , and a nearly massless, (Goldstone-like) pseudoscalar particle with 0<mb≲2.7×10-6 eV . One or both particles can be part of dark matter. There are coherent long-range interactions (at range ~ 1/mb≳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/mb), 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.