Marriage between the baryonic and dark matters

Abstract

Abstract. The baryonic and dark matter fractions can be both generated simultaneously and with comparable amounts, if dark matter is constituted by the baryons of the mirror world, a parallel hidden sector with the same (or similar) microphysics as that of the observable world.Keywords: Early Universe, Leptogenesis, Baryogenesis, Dark Matter PACS: 11.30. Er, 11.30Fs, 14.60.St, 95.30.Cq, 95.35.+d, Baryonic and Dark Matter in the Universe:Cosmological observations indicate that the Universe is nearly flat, with the energy density very close to critical: Ω tot = 1. The non-relativistic matter in the Universe consists of two components, baryonic (B) and dark (D). The recent data fits imply [1]:where h = 0.73 ± 0.02 is the Hubble parameter. Hence, the matter gives only a smaller fraction of the total energy density: Ω M = Ω B + Ω D = 0.24 ± 0.02, while the rest is attributed to dark energy (cosmological term):The closeness of Ω Λ and Ω M (Ω Λ /Ω M = 3.2 ± 0.3), known as cosmic coincidence, may have an antrophic origin: the matter and vacuum energy densities scale differently with the expansion of the Universe: ρ M ∼ a −3 and ρ Λ ∼ const., and thus they must coincide at some moment. So, it is our good luck to assist the epoch when ρ M ∼ ρ Λ : in the earlier Universe one had ρ M ≫ ρ Λ and in the later Universe one will have ρ M ≪ ρ Λ . Moreover, if ρ Λ would be just few times bigger, no galaxies could be formed and thus there would be nobody to rise the question.The closeness between Ω D and Ω B (Ω D /Ω B = 4.7 ± 0.3) gives rise to more painful problem. Both ρ D and ρ B scale as ∼ a −3 with the Universe expansion, and their ratio should not dependent on time. Why then these two fractions are comparable, if they have a drastically different nature and different origin?The baryon mass density is ρ B = m B n B , where m B ≃ 1 GeV is the nucleon mass, and n B is the baryon number density. Hence, Ω B h 2 = 2.6 × 10 8 (n B /s), s being the entropy density, and so eq. . The origin of non-zero baryon asymmetry Y B , which presumably was produced in a very early universe as a tiny difference n B = n b − nb between the baryon and anti-baryon abundances, is yet unclear. The popular mechanisms known as GUT Baryogenesis, Leptogenesis, Electroweak Bariogenesis, etc., all are conceptually based on out-of-

DAMA annual modulation and mirror Dark Matter

“…T ′ /T < 0.2, cosmological limit at which mirror matter with Ω ′ B > Ω B is still allowed by the CMB and large scale tests, we get an upper limit Ω ′ B /Ω B < 5 or so. In this way, mirror matter could represent an entire amount of Dark Matter [63,66,86,67].…”

New Directions in Direct Dark Matter Searches

“…Why these two fractions are then comparable, if the ordinary and the dark sectors have a drastically different nature and different origin? An hidden parallel sector (mirror world 6 ) may shed light on this cosmic coincident problem [87]. Indeed, it is tantalizing to imagine that the dark world could be similarly complex (CP-violating and asymmetric), full of forces (e.g.…”

Mirror symmetry: from active and sterile neutrino masses to baryonic and dark matter asymmetries

“…If the light sterile neutrinos are eventually confirmed, we need explain not only the existence and small masses of the sterile neutrinos but also the mixing between the active and sterile neutrinos. Such sterile neutrinos can naturally appear in the mirror universe models discussed in the literature [42][43][44][45][46][47][48][49][50][51]. There are also other ideas for the light sterile neutrinos [52][53][54][55][56][57][58].…”