Baryon Asymmetry, Dark Matter and Quantum Chromodynamics

We propose a new scenario to explain the observed cosmological asymmetry between matter and antimatter, based on nonperturbative physics at the QCD scale. Our scenario relies on a mechanism of separation of matter and antimatter which would be in two different phases: conventional hadronic phase and novel, color superconducting phase. We argue that chunks of quarks or antiquarks in condensed color superconducting phase may be formed during the QCD phase transition and they may serve as dark matter. All three Sakharov’s criteria are satisfied when the condensate forms, and we argue that the mechanism, which produces a separation of baryonic charge, can leave a net asymmetry of baryons in the hadronic phase. We then explain why such a scenario does not contradict the current observational data on antimatter in the Universe. This is due to the specific interaction features of the matter in color superconducting phase with “normal” matter in hadronic phase. A similar property of the interactions at the interface of ordinary metals and superconductors is well known in the literature as “Andreev Reflection”. The observed cosmological ratio between the energy densities of dark and baryonic matter, ΩDM ∼ ΩB within an order of magnitude, finds its natural explanation in this scenario: both contributions to Ω originated from the same physics at the same instant during the QCD phase transition. The baryon to entropy ratio nB/nγ ∼ 10 would also be a natural outcome in this scenario.