Back to Search
Start Over
Can bigravity gravitational baryogenesis explain the CMB 143 GHz excess line?
- Source :
- Gravitation and Cosmology. 23:162-170
- Publication Year :
- 2017
- Publisher :
- Pleiades Publishing Ltd, 2017.
-
Abstract
- It has been recently claimed [arXiv: 1510.00126], that the 143 GHz excess line in the Cosmic MicrowaveBackground (CMB) spectrumcould be explained by a collision of our Universe with an alternate Universe in which the baryon to entropy ratio is 65 times larger than the corresponding value measured for ourUniverse. This 143 GHz excess line is due to baryons, as was claimed, since the excess line corresponds to the recombination epoch, while the rest of the CMB signal is free of such excess lines. Thus the excess line is ascribed to an effect of collision of our Universe with a parallel universe. In this paper, we propose an alternative mechanism to explain the 143 GHz excess CMB line by using a simple bimetric gravity model which makes use of two metrics, the foreground metric g μν and the background metric f μν. The foreground Universe describes our Universe, and the background Universe is assumed to be underlying. The metrics are chosen to satisfy $${f_{\mu \nu }} = D_{{g_{\mu \nu }}}^2$$ , and the bimetric gravity model is constrained in such a way that the resulting Einstein equations for the background and foreground Universe are identical. In effect, the foreground and background Universe are indistinguishable at the cosmological solutions level. However, for the choices of the metrics we made, the scalar curvatures of the foreground and background Universes, namely R g and R f, are related by R f = 1/D 2, which can effectively result in different baryon to entropy ratios for the two Universes, via the gravitational baryogenesis mechanism. According to the gravitational baryogenesis mechanism, the baryon to entropy ratio is $$\eta B = \dot R/M_*^2T$$ , which means that the baryon to entropy ratio for the foreground and the background Universes we chose, namely ηB(g) and ηB(f), satisfy the relation $$\eta B\left( f \right) = \frac{1}{{{D^2}}}\eta B\left( g \right)$$ , and if D is chosen as $$D = 1/\sqrt {65} $$ , this could explain the 143 GHz excess line. The resulting phenomenological picture is quite appealing, since in the context of our bimetric gravity model, the foreground and background Universes coexist and are indistinguishable at the cosmological solutions level, but they are distinguishable only via the gravitational baryogenesis mechanism, which results in a baryon to entropy ratio for the background Universe, which is 65 time larger from the one corresponding to our Universe.
- Subjects :
- Physics
Particle physics
010308 nuclear & particles physics
Parallel universe
media_common.quotation_subject
Cosmic microwave background
Cosmic background radiation
Astronomy and Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
01 natural sciences
Universe
Gravitation
Baryon
Baryogenesis
Bimetric gravity
0103 physical sciences
010306 general physics
media_common
Subjects
Details
- ISSN :
- 19950721 and 02022893
- Volume :
- 23
- Database :
- OpenAIRE
- Journal :
- Gravitation and Cosmology
- Accession number :
- edsair.doi...........acd347f8aaeffe8f78820be0f1a81a52