Abstract
We study the experimental constraints on a model of a two-component dark matter, consisting of the QCD axion, and a scalar particle, both contributing to the dark matter relic abundance of the Universe. The global Peccei-Quinn symmetry of the theory can be spontaneously broken down to a residual $\mathbb{Z}_2$ symmetry, thereby identifying this scalar as a stable weakly interacting massive particle, i.e., a dark matter candidate, in addition to the axion. We perform a comprehensive study of the model using the latest data from dark matter direct and indirect detection experiments, as well as new physics searches at the Large Hadron Collider. We find that although the model is mostly constrained by the dark matter detection experiments, it is still viable around a small region of the parameter space where the scalar dark matter is half as heavy as the Standard Model Higgs. In this allowed region, the bounds from these experiments are evaded due to a cancellation mechanism in the dark matter--Higgs coupling. The collider search results, however, are shown to impose weak bounds on the model.
Highlights
The evidence of cold dark matter (CDM) is overwhelming from the cosmological data, even though its detection and identification continue to be one of the most interesting and challenging problems today [1]
The gray shaded region is ruled out by the relic constraints. We allow for both χ1 as well as the axion to contribute to the DM relic density
We have performed a comprehensive study of a two-component dark matter model, consisting of the QCD axion and an electromagnetic charge neutral scalar particle, both contributing to the relic density
Summary
The evidence of cold dark matter (CDM) is overwhelming from the cosmological data, even though its detection and identification continue to be one of the most interesting and challenging problems today [1]. We study a two-component DM model consisting of a WIMP and the axion as the DM candidates This type of model gives a unifying scenario where the PQ field, which is motivated to solve the strong-CP problem, and the WIMP, which is a natural solution to DM puzzle, can be accommodated in a single go [46,49]. Breaking of the Uð1ÞPQ and the electroweak symmetry leads to a mixing between the Higgs and the radial part of the PQ scalar, which leads to interesting phenomenological consequences The advantage of this model is that the axions have very weak interactions with the SM, the coupling between this dark scalar and the SM Higgs doublet provides a portal to test this model in different DM detection experiments, both direct and indirect.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
