The Z7 model of three-component scalar dark matter

Abstract

We investigate, for the first time, a scenario where the dark matter consists of three complex scalar fields that are stabilized by a single Z7 symmetry. As an extension of the well-known scalar Higgs-portal, this Z7 model is also subject to important restrictions arising from the relic density constraint and from direct detection experiments. Our goal in this paper is to find and characterize the viable regions of this model, and to analyze its detection prospects in future experiments. First, the processes that affect the relic densities are identified (they include semiannihilations and conversions) and then incorporated into the Boltzmann equations for the dark matter abundances, which are numerically solved with micrOMEGAs. By means of random scans of the parameter space, the regions consistent with current data, including the recent direct detection limit from the LZ experiment, are selected. Our results reveal that the Z7 model is indeed viable over a wide range of dark matter masses and that both conversions and semiannihilations play an important role in determining the relic densities. Remarkably, we find that in many cases all three of the dark matter particles give rise to observable signals in future direct detection experiments, providing a suitable way to test this scenario.

Symmetries for the 4HDM: extensions of cyclic groups

“…Details of the scalar sector in such models are often mentioned in passing, but they can contain symmetry-driven features or limitations. Just to give a recent example of a less-studied construction, [81] investigated the scenario with three dark matter candidates shaped by the symmetry group Z 7 . We expect that the methods and the results which we present here for the 4HDM will be of relevance to these multi-scalar models equipped with global symmetries.…”

Phase transitions and gravitational waves in a model of ℤ3 scalar dark matter

“…for generalisations). With higher symmetries, such as Z7, and more fields, one can have even three-component DM[32].2 It is possible that the Z3 symmetry is a remnant of breaking of a U(1) group, see e.g [35][36][37][38]…”