Fermion number violating effects in low scale leptogenesis

Eijima, Shintaro; Shaposhnikov, Mikhail

doi:10.1016/j.physletb.2017.05.068

Cited by 48 publications

(101 citation statements)

References 52 publications

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“…Furthermore, the lepton asymmetries have an intriguing structure, being evenly distributed amongst all flavours and settling into a stationary state (see also ref. [12]). We now follow that state down to lower temperatures, at which the GeV-scale right-handed neutrinos freeze out and decay.…”

Section: Introductionmentioning

confidence: 99%

Sterile neutrino dark matter via GeV-scale leptogenesis?

Ghiglieri

Laine

2019

J. High Energ. Phys.

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It has been proposed that in a part of the parameter space of the Standard Model completed by three generations of keV...GeV right-handed neutrinos, neutrino masses, dark matter, and baryon asymmetry can be accounted for simultaneously. Here we numerically solve the evolution equations describing the cosmology of this scenario in a 1+2 flavour situation at temperatures T ≤ 5 GeV, taking as initial conditions maximal lepton asymmetries produced dynamically at higher temperatures, and accounting for late entropy and lepton asymmetry production as the heavy flavours fall out of equilibrium and decay. For 7 keV dark matter mass and other parameters tuned favourably, ∼ 10% of the observed abundance can be generated. Possibilities for increasing the abundance are enumerated.

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Section: Introductionmentioning

confidence: 99%

Sterile neutrino dark matter via GeV-scale leptogenesis?

Ghiglieri

Laine

2019

J. High Energ. Phys.

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“…The second purpose is to compare, within the same formalism, which of the L-violating (LV) and L-conserving (LC) contributions dominates the production of the baryon asymmetry as a function of the parameters. In fact, evolution equations including the L-violating contribution have been derived long ago in the density-matrix formalism [3,7], and also very recently [15,16], but this was considered as numerically irrelevant for the generation of the baryon asymmetry. This stems from the fact that L-violating processes have been thought to lead to a negligible contribution due to the m 2 N /T 2 suppression factor discussed above (and thus approximated as zero in the solution of the evolution equations for baryogenesis [7]) or, very recently, because the corresponding obtained rates were considered as numerically "not significant" [15].…”

Section: Introductionmentioning

confidence: 99%

Baryogenesis from L -violating Higgs-doublet decay in the density-matrix formalism

Hambye

Teresi

2017

Phys. Rev. D

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We compute in the density-matrix formalism the baryon asymmetry generated by the decay of the Higgs doublet into a right-handed (RH) neutrino and a Standard Model lepton. The emphasis is put on the baryon asymmetry produced by the total lepton-number violating decay. From the derivation of the corresponding evolution equations, and from their integration, we find that this contribution is fully relevant for large parts of the parameter space. This confirms the results found recently in the CP-violating decay formalism with thermal corrections and shows in particular that the lepton-number violating processes are important not only for high-scale leptogenesis but also when the RH-neutrino masses are in the GeV range. For large values of the Yukawa couplings, we also find that the strong washout is generically much milder for this total lepton-number violating part than for the usual RH-neutrino oscillation flavour part.

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“…The existence of sphaleron processes is however not confirmed experimentally and numerous high energy theories predict a significantly larger lepton asymmetry, e.g. [4][5][6][7][8]. Thus, lepton asymmetry is a key parameter to better constrain models of the creation of the matter-antimatter asymmetry of the Universe.…”

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confidence: 99%

“…Our constraints 7 The Planck 2015 analysis takes the mass defect into account, whereas the Planck 2013 analysis [35] also neglects it. 8 Our fitting formula for Yp and y DP are based on calculations with the AlterBBN default value τn = 885.7 s.…”

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confidence: 99%

Improved constraints on lepton asymmetry from the cosmic microwave background

Oldengott¹,

Schwarz²

2017

EPL

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-A cosmic lepton asymmetry η l = (n l − nl)/nγ affects the primordial helium abundance and the expansion rate of the early Universe. Both of these effects have an impact on the anisotropies of the cosmic microwave background (CMB). We derive constraints on the neutrino chemical potentials from the Planck 2015 data, assuming equal lepton flavour asymmetries and negligible neutrino masses. We find ξ = −0.002−0.111 (95% CL) for the chemical potentials, which corresponds to −0.085 ≤ η l ≤ 0.084. Our constraints on the lepton asymmetry are significantly stronger than previous constraints from CMB data analysis and we argue that they are more robust than those from primordial light element abundances. The resulting constraints on the primordial helium and deuterium abundances are consistent with those from direct measurements.

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Fermion number violating effects in low scale leptogenesis

Cited by 48 publications

References 52 publications

Sterile neutrino dark matter via GeV-scale leptogenesis?

Sterile neutrino dark matter via GeV-scale leptogenesis?

Baryogenesis from L -violating Higgs-doublet decay in the density-matrix formalism

Improved constraints on lepton asymmetry from the cosmic microwave background

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