Enlarging the window for radiative leptogenesis

Branco, G.C.; Felipe, R. González; Joaquim, F. R.; Nobre, Bruno

doi:10.1016/j.physletb.2005.11.070

Cited by 70 publications

(49 citation statements)

References 52 publications

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“…This corresponds approximately to one of the scenarios considered in a recent study of radiative leptogenesis [18] with two right-handed neutrinos quasi-degenerate and a third right-handed neutrino decoupled M 1 ≃ M 2 ≪ M 3 . If only y 12 = 0 the calculation of η B proceeds in the same way since to a good approximation only ν 1 R and ν 2 R contribute to the CP asymmetry.…”

Section: Two Flavour Limitmentioning

confidence: 54%

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Another look at minimal lepton flavour violation, leptogenesis and the ratioM_ν/Λ_LFV

Branco

Buras

Jäger

et al. 2007

J. High Energy Phys.

127

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We analyze lepton flavour violation (LFV), as well as generation of the observed baryon-antibaryon asymmetry of the Universe (BAU) within a generalized minimal lepton flavour violation (MLFV) framework where we allow for CP violation both at low and high energies. The generation of BAU is obtained through radiative resonant leptogenesis (RRL), where starting with three exactly degenerate right-handed neutrinos at Λ GUT , we demonstrate explicitly within the SM and the MSSM that the splittings between their masses at the see-saw scale M ν , generated by renormalization group effects, are sufficient for a successful leptogenesis for M ν even as low as 10 6 GeV. The inclusion of flavour effects plays an important role in this result and can lead to the observed BAU even in the absence of CP violation beyond the PMNS phases. The absence of a stringent lower bound on M ν in this type of leptogenesis allows to easily satisfy present and near future upper bounds on µ → eγ and other charged lepton flavour violating (LFV) processes even for Λ LFV = O(1 TeV). We find, that the MLFV framework in the presence of heavy righthanded neutrinos and leptogenesis is not as predictive as MFV in the quark sector and point out that without a specific MLFV model, there is a rich spectrum of possibilities for charged LFV processes and for their correlation with low energy neutrino physics and the LHC physics, even if the constraint from the observed BAU is taken into account. While certain qualitative features of our analysis confirm findings of Cirigliano et al., at the quantitative level we find phenomenologically important differences. We explain the origin of these differences.

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Section: Two Flavour Limitmentioning

confidence: 54%

“…In [18], leptogenesis was studied in the framework of a model where there are three right-JHEP09 (2007)004 handed neutrinos, with masses M 1 ≈ M 2 ≪ M 3 . We will discuss this scenario below as a special limit of the MLFV framework.…”

Section: Preliminariesmentioning

confidence: 99%

Another look at minimal lepton flavour violation, leptogenesis and the ratioM_ν/Λ_LFV

Branco

Buras

Jäger

et al. 2007

J. High Energy Phys.

127

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“…Although theoretically challenging, it is possible to construct models in which the heavy Majorana neutrino mass splitting is naturally as small as the decay width at the leptogenesis scale. For instance, in the socalled radiative resonant leptogenesis scenario (Branco et al, 2006a;González Felipe et al, 2004;Turzynski, 2004), the required splitting can be generated by the renormalization group running from the GUT scale down to the leptogenesis scale, assuming that the heavy Majorana neutrinos are exactly degenerate at the GUT scale. The assumption of a completely degenerate righthanded neutrino spectrum at the GUT scale is compatible with the solar and atmospheric neutrino oscillation data (González Felipe and Joaquim, 2001).…”

Section: Type I Seesaw Leptogenesismentioning

confidence: 99%

“…The assumption of a completely degenerate righthanded neutrino spectrum at the GUT scale is compatible with the solar and atmospheric neutrino oscillation data (González Felipe and Joaquim, 2001). Such a degeneracy can be achieved, for instance, by imposing some discrete or Abelian symmetries (Branco et al, 2006a), or in models with minimal lepton flavor violation (Branco et al, 2007a;Cirigliano et al, 2008Cirigliano et al, , 2007 as described in Sec. II.G.…”

Section: Type I Seesaw Leptogenesismentioning

confidence: 99%

LeptonicCPviolation

Branco¹,

Felipe

Joaquim³

2012

Rev. Mod. Phys.

Self Cite

205

188

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Several topics on CP violation in the lepton sector are reviewed. A few theoretical aspects concerning neutrino masses, leptonic mixing, and CP violation will be covered, with special emphasis on seesaw models. A discussion is provided on observable effects which are manifest in the presence of CP violation, particularly, in neutrino oscillations and neutrinoless double beta decay processes, and their possible implications in collider experiments such as the LHC. The role that leptonic CP violation may have played in the generation of the baryon asymmetry of the Universe through the mechanism of leptogenesis is also discussed.

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“…This possibility has been considered in many works [14,15,16]. In [8] an analytical condition for the validity of a calculation of the efficiency factor κ f 1 in the HL was found.…”

Section: Introductionmentioning

confidence: 99%

Leptogenesis beyond the limit of hierarchical heavy neutrino masses

Blanchet¹,

Bari²

2006

J. Cosmol. Astropart. Phys.

121

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We calculate the baryon asymmetry of the Universe in thermal leptogenesis beyond the usual lightest right-handed (RH) neutrino dominated scenario (N 1 DS) and in particular beyond the hierarchical limit (HL), M 1 ≪ M 2 ≪ M 3 , for the RH neutrino mass spectrum. After providing some orientation among the large variety of models, we first revisit the central role of the N 1 DS, with new insights on the dynamics of the asymmetry generation and then discuss the main routes departing from it, focusing on models beyond the HL. We study in detail two examples of 'strong-strong' washout scenarios: one with 'maximal phase' and the limit of very large M 3 , studying the effects arising when δ 2 ≡ (M 2 − M 1 )/M 1 is small. We extend analytical methods already applied to the N 1 DS showing, for example, that, in the degenerate limit (DL), the efficiency factors of the RH neutrinos become equal with the single decay parameter replaced by the sum. Both cases disprove the misconception that close RH neutrino masses necessarily lead to a final asymmetry enhancement and to a relaxation of the lower bounds on M 1 and on the initial temperature of the radiationdominated expansion. We also explain why leptogenesis tends to favor normal hierarchy compared to inverted hierarchy for the left-handed neutrino masses.

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Enlarging the window for radiative leptogenesis

Cited by 70 publications

References 52 publications

Another look at minimal lepton flavour violation, leptogenesis and the ratioM_ν/Λ_LFV

Another look at minimal lepton flavour violation, leptogenesis and the ratioM_ν/Λ_LFV

LeptonicCPviolation

Leptogenesis beyond the limit of hierarchical heavy neutrino masses

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Enlarging the window for radiative leptogenesis

Cited by 70 publications

References 52 publications

Another look at minimal lepton flavour violation, leptogenesis and the ratioMν/ΛLFV

Another look at minimal lepton flavour violation, leptogenesis and the ratioMν/ΛLFV

LeptonicCPviolation

Leptogenesis beyond the limit of hierarchical heavy neutrino masses

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Product

Resources

About

Another look at minimal lepton flavour violation, leptogenesis and the ratioM_ν/Λ_LFV

Another look at minimal lepton flavour violation, leptogenesis and the ratioM_ν/Λ_LFV