Cosmological axion and a quark nugget dark matter model

Shuailiang Ge, Xunyu Liang, Ariel Zhitnitsky
2018 Physical Review D  
We study a dark matter (DM) model offering a very natural explanation of two (naively unrelated) problems in cosmology: the observed relation Ω_ DM∼Ω_ visible and the observed asymmetry between matter and antimatter in the Universe, known as the "baryogenesis" problem. In this framework, both types of matter (dark and visible) have the same QCD origin, form at the same QCD epoch, and both proportional to one and the same dimensional parameter of the system, Λ_ QCD, which explains how these two,
more » ... naively distinct, problems could be intimately related, and could be solved simultaneously within the same framework. More specifically, the DM in this model is composed by two different ingredients: the (well- studied) DM axions and (less-studied) the quark nuggets made of matter or antimatter. The focus of the present work is the quantitative analysis of the relation between these two distinct components contributing to the dark sector of the theory determined by Ω_ DM≡ [Ω_ DM( nuggets)+ Ω_ DM( axion)]. We argue that the nugget's DM component always traces the visible matter density, i.e. Ω_ DM( nuggets)∼Ω_ visible and this feature is not sensitive to the parameters of the system such as the axion mass m_a or the misalignment angle θ_0. It should be contrasted with conventional axion production mechanism due to the misalignment when Ω_ DM( axion) is highly sensitive to the axion mass m_a and the initial misalignment angle θ_0. We also discuss the constraints on this model related to the inflationary scale H_I, non-observation of the isocurvature perturbations, r_T < 0.12, and also, varies axions search experiments.
doi:10.1103/physrevd.97.043008 fatcat:fou5nt5lnfdofdcn4px65fjpua