Cosmological evolution of thermal relic particles in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>f</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mi>R</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math>gravity

Capozziello, Salvatore; Galluzzi, V.; Lambiase, Gaetano; Pizza, Liberato

doi:10.1103/physrevd.92.084006

Cited by 17 publications

(11 citation statements)

References 116 publications

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“…It is well known that the physics of the universe at early times constitutes a great laboratory to explore physics beyond the standard cosmological model. For instance, torsion in f (T ) theories of gravity can be constrained by big bang nucleosynthesis [68], modifications on the evolution of the thermal relic particles (particles like WIMPs (weakly interactive massive particles)) within f (R) gravity context are also taken into account in [69]. Thus, it is worth noting that the nonzero ratio of baryon-to-entropy of the universe could be a potential quantity to constrain extended theories of gravity too.…”

Section: Discussionmentioning

confidence: 99%

Gravitational baryogenesis in running vacuum models

Oikonomou

Pan

Nunes

2017

Int. J. Mod. Phys. A

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We study the gravitational baryogenesis mechanism for generating baryon asymmetry in the context of running vacuum models. Regardless if these models can produce a viable cosmological evolution, we demonstrate that they produce a non-zero baryon-to-entropy ratio even if the universe is filled with conformal matter. This is a sound difference between the running vacuum gravitational baryogenesis and the Einstein-Hilbert one, since in the latter case, the predicted baryon-to-entropy ratio is zero. We consider two well known and most used running vacuum models and show that the resulting baryon-to-entropy ratio is compatible with the observational data. Moreover, we also show that the mechanism of gravitational baryogenesis may constrain the running vacuum models. 95.36.+x, 95.35.+d * Electronic address: v.k.oikonomou1979@gmail.com † Electronic address: span@iiserkol.ac.in ‡ Electronic address: rafadcnunes@gmail.com 1 However, it deserves to be mentioned that the theory of gravitational modifications has also been found to explain the late time accelerated expansion without any need of dark energy [2][3][4][5][6][7][8][9][10][11].

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Section: Discussionmentioning

confidence: 99%

Gravitational baryogenesis in running vacuum models

Oikonomou

Pan

Nunes

2017

Int. J. Mod. Phys. A

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“…Different values for the parameter ν appear in various modified cosmological scenarios [16,[115][116][117][118][119]: ν = 2 in Randall-Sundrum type II brane cosmology [120], ν = 1 in kination models [121][122][123], ν = 0 in cosmologies with an overall boost of the Hubble expansion rate like in the case of a large number of additional relativistic degrees of freedom in the thermal plasma [16], ν = 2/n − 2 in f (x) cosmology with f (x) = x + α x n , where x = R, T ; R and T being the scalar curvature and the scalar torsion, respectively [124][125][126][127]. 2 If the evolution of the Universe is adiabatic, and therefore the SM entropy is conserved, the temperature and the scale factor are related via…”

Section: Parametrizationmentioning

confidence: 99%

Primordial gravitational waves in nonstandard cosmologies

Bernal

Hajkarim

2019

Phys. Rev. D

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Assuming that inflation is followed by a phase where the energy density of the Universe is dominated by a component with a general equation of state, we evaluate the spectrum of primordial gravitational waves induced in the post-inflationary Universe. We show that if the energy density of the Universe is dominated by a component φ before Big Bang nucleosynthesis, its equation of state could be constrained by gravitational wave experiments depending on the ratio of energy densities of φ and radiation, and also the temperature at the end of the φ dominated era. Also, we discuss the impact of scale dependence of tensor modes on the primordial gravitational wave spectrum during the φ-domination. These models are motivated by beyond Standard Model physics and scenarios for non-thermal production of dark matter in the early Universe. We also constrain the parameter space of the tensor spectral index and the tensor-to-scalar ratio, using the experimental limits from gravitational wave experiments.

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“…2 Investigations along these lines have been performed in different cosmological scenarios [63][64][65][66][67][68][69][70][71][72], where The parameter ν labels cosmological models: ν = 2 in Randall-Sundrum type II brane cosmology [73], ν = 1 in kination models [74][75][76][77], ν = 0 in cosmologies with an overall boost of the Hubble expansion rate [63], ν = − 0.8 in scalar-tensor cosmology [63,78], ν = 2/n − 2 in f (R) cosmology, with f (R) = R + α R n [79,80]. In terms of the modified expansion rate (3.2), it then follows that the inverse decay processes (2.6) takes the form…”

Section: Pev Neutrinos In Modified Cosmologiesmentioning

confidence: 99%

PeV IceCube signals and Dark Matter relic abundance in modified cosmologies

2018

Self Cite

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The discovery by the IceCube experiment of a high-energy astrophysical neutrino flux with energies of the order of PeV, has opened new scenarios in astroparticles physics. A possibility to explain this phenomenon is to consider the minimal models of Dark Matter (DM) decay, the 4-dimensional operator ∼ y αχ L L α H χ , which is also able to generate the correct abundance of DM in the Universe. Assuming that the cosmological background evolves according to the standard cosmological model, it follows that the rate of DM decay χ ∼ |y αχ | 2 needed to get the correct DM relic abundance ( χ ∼ 10 −58 ) differs by many orders of magnitude with respect that one needed to explain the IceCube data ( χ ∼ 10 −25 ), making the four-dimensional operator unsuitable. In this paper we show that assuming that the early Universe evolution is governed by a modified cosmology, the discrepancy between the two the DM decay rates can be reconciled, and both the IceCube neutrino rate and relic density can be explained in a minimal model.

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Cosmological evolution of thermal relic particles inf(R)gravity

Cited by 17 publications

References 116 publications

Gravitational baryogenesis in running vacuum models

Gravitational baryogenesis in running vacuum models

Primordial gravitational waves in nonstandard cosmologies

PeV IceCube signals and Dark Matter relic abundance in modified cosmologies

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