Primordial Antimatter in the Contemporary Universe

In some baryogenesis scenarios, the universe acquires a non-vanishing average baryonic charge, but the baryon to photon ratio is not spatially constant and can be even negative in some space regions. This allows for existence of lumps of antimatter in our neighborhood and the possibility that very compact antimatter objects make a part of cosmological dark matter. Here I discuss the peculiar signatures which may be observed in a near future. One can conclude from simple considerations that there is much more matter than antimatter around us [1]. However, the origin of matter–antimatter asymmetry in the universe is unknown: the Standard Model of particle physics is certainly unable to explain it and new physics is necessary [2]. Assuming a homogeneous and isotropic universe, from the Big Bang Nucleosynthesis