Degenerate minimal see-saw and leptogenesis

TURZYSKI, K

doi:10.1016/s0370-2693(04)00526-x

Cited by 7 publications

(12 citation statements)

References 16 publications

(27 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As expected, when ω 2 = π/2 the results of the minimal seesaw scenario considered in [14,15] are recovered. Thus, the new contributions coming from the mixing with the heaviest Majorana neutrino N 3 turn out to be crucial in this case for the mechanism to be viable.…”

Section: The Case Msupporting

confidence: 78%

“…In the present framework, a sufficiently small heavy neutrino mass splitting will be generated through the RG running effects. The latter turn out to be crucial in this case [14,15,17].…”

Section: Radiative Leptogenesismentioning

confidence: 93%

“…In the latter case, nonvanishing and sufficiently large CP asymmetries, which are proportional to the charged-lepton τ Yukawa coupling and weakly dependent on the heavy Majorana neutrino mass scale, are generated. Although in the SM framework the resulting baryon asymmetry turns out to be (by a factor of two) below the observed value [14], this mechanism can be successfully implemented in its minimal supersymmetric extension (MSSM) [15]. However, it is worth emphasizing that the above results have been obtained in a minimal seesaw scenario with only two heavy neutrinos.…”

Section: Introductionmentioning

confidence: 89%

“…This condition can always be guaranteed without loss of generality. Indeed, when M 1 = M 2 there is the freedom to rotate the right-handed neutrino fields N 1,2 with a real orthogonal matrix that does not change M R , but rotates Y ν to the appropriate basis [14,15]. In terms of the parametrisation (3), this is equivalent to a redefinition of the real part of the complex angle θ 1 .…”

Section: Radiative Leptogenesismentioning

confidence: 99%

“…Another possibility which has been recently explored [14,15] relies on the fact that radiative effects, induced by the renormalization group (RG) running from high to low energies, can naturally lead to a sufficiently small neutrino mass splitting at the leptogenesis scale. In the latter case, nonvanishing and sufficiently large CP asymmetries, which are proportional to the charged-lepton τ Yukawa coupling and weakly dependent on the heavy Majorana neutrino mass scale, are generated.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Enlarging the window for radiative leptogenesis

Branco¹,

Felipe²,

Joaquim

et al. 2006

Physics Letters B

View full text Add to dashboard Cite

We investigate the scenario of resonant thermal leptogenesis, in which the leptonic asymmetries are generated through renormalization group corrections induced at the leptogenesis scale. In the framework of the standard model extended by three right-handed heavy Majorana neutrinos with masses M 1 = M 2 ≪ M 3 at some high scale, we show that the mass splitting and CP -violating effects induced by renormalization group corrections can lead to values of the CP asymmetries large enough for a successful leptogenesis. In this scenario, the low-energy neutrino oscillation data can also be easily accommodated. The possibility of having an underlying symmetry behind the degeneracy in the right-handed neutrino mass spectrum is also discussed.

show abstract

Section: The Case Msupporting

confidence: 78%

“…In the present framework, a sufficiently small heavy neutrino mass splitting will be generated through the RG running effects. The latter turn out to be crucial in this case [14,15,17].…”

Section: Radiative Leptogenesismentioning

confidence: 93%

Section: Introductionmentioning

confidence: 89%

Section: Radiative Leptogenesismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Enlarging the window for radiative leptogenesis

Branco¹,

Felipe²,

Joaquim

et al. 2006

Physics Letters B

View full text Add to dashboard Cite

show abstract

Running Neutrino Mass Parameters in See-Saw Scenarios

Antusch

Kersten

Lindner

et al. 2005

J. High Energy Phys.

401

584

View full text Add to dashboard Cite

We systematically analyze quantum corrections in see-saw scenarios, including effects from above as well as below the see-saw scales. We derive approximate renormalization group equations for neutrino masses, lepton mixings and CP phases, yielding an analytic understanding and a simple estimate of the size of the effects. Even for hierarchical masses, they often exceed the precision of future experiments. Furthermore, we provide a software package allowing for a convenient numerical renormalization group analysis, with heavy singlets being integrated out successively at their mass thresholds. We also discuss applications to model building and related topics.This relation emerges from integrating out heavy, singlet neutrinos with mass matrix M. The Dirac neutrino mass m Dirac ν is proportional to the neutrino Yukawa coupling Y ν . Clearly, the see-saw operates at high energy scales while its implications are measured by experiments at low scales. Therefore, the neutrino masses given by Eq. (1) are subject to quantum corrections, i.e. they are modified by renormalization group (RG) running.The running of neutrino masses and lepton mixing angles has been investigated intensively in the literature. For non-hierarchical neutrino mass spectra, RG effects can be very large and they can have interesting implications for model building. For example, lepton mixing angles can be magnified [6,7,8,9,10], bimaximal mixing at high energy can be compatible with low-energy experiments [11,12,13] or the small mass splittings can be generated from exactly degenerate light neutrinos [14,15,16,17,18,19]. On the other hand, facing the high precision of future neutrino experiments, rather small RG corrections are important as well. For instance, deviations from θ 13 = 0 or maximal mixing θ 23 = π/4 are induced by RG effects [20,21,22] also for a hierarchical spectrum. However, in most studies only the running of the dimension 5 operator has been considered, which is only appropriate for the energy range below the mass scale of the heavy singlets.The importance of including the effects from energy ranges above and between these mass thresholds when analyzing RG effects in GUT models has been pointed out in [23,24,25,26,27,11,8,12,13,21]. They are typically at least as important as the effects from below the thresholds since the relevant couplings, i.e. the entries of Y ν , can be of order one, regardless of tan β. 1 Previous studies have investigated the RG effects above the see-saw scales mainly numerically.In this paper we derive formulae which allow to understand the running of the neutrino parameters above the see-saw scales analytically. We further provide a software package for analyzing the RG evolution (with correct treatment of non-degenerate see-saw scales) numerically. We apply our results to investigate consequences of the running above the see-saw scales for model building and leptogenesis and compare the size of RG corrections to the precision of future experiments.The paper is organized as follows: In Sec. 2, we review ho...

show abstract

Leptonic CP violation: zero, maximal or between the two extremes

Farzan

Smirnov

2007

J. High Energy Phys.

View full text Add to dashboard Cite

Discovery of the CP-violation in the lepton sector is one of the challenges of the particle physics. We search for possible principles, symmetries and phenomenological relations that can lead to particular values of the CP-violating Dirac phase, δ. In this connection we discuss two extreme cases: the zero phase, δ = 0, and the maximal CP-violation, δ = ±π/2, and relate them to the peculiar pattern of the neutrino mixing. The maximal CP-violation can be related to the ν µ − ν τ reflection symmetry. We study various aspects of this symmetry and introduce a generalized reflection symmetry that can lead to an arbitrary phase that depends on the parameter of the symmetry transformation. The generalized reflection symmetry predicts a simple relation between the Dirac and Majorana phases. We also consider the possibility of certain relations between the CP-violating phases in the quark and lepton sectors.

show abstract

Degenerate minimal see-saw and leptogenesis

Cited by 7 publications

References 16 publications

Enlarging the window for radiative leptogenesis

Enlarging the window for radiative leptogenesis

Running Neutrino Mass Parameters in See-Saw Scenarios

Leptonic CP violation: zero, maximal or between the two extremes

Contact Info

Product

Resources

About