μ–τ interchange symmetry and lepton mixing

We propose a complex extension of µτ permutation antisymmetry in the neutrino Majorana matrix M ν . The latter can be realized for the Lagrangian by appropriate CP transformations on the neutrino fields. The resultant form of M ν is shown to be simply related to that with a complex (CP) extension of µτ permutation symmetry, with identical phenomenological consequences, though their group theoretic origins are quite different. We investigate those consequences in detail for the minimal seesaw induced by two strongly hierarchical right-chiral neutrinos N 1 and N 2 with the result that the Dirac phase is maximal while the two Majorana phases are either 0 or π. We further provide an uptodate discussion of the ββ0ν process vis-a-vis ongoing and forthcoming experiments. Finally, a thorough treatment is given of baryogenesis via leptogenesis in this scenario, primarily with the assumption that the lepton asymmetry produced by the decays of N 1 only matters here with the asymmetry produced by N 2 being washed out. Tight upper and lower bounds on the mass of N 1 are obtained from the constraint of obtaining the correct observed range of the baryon asymmetry parameter and the role played by N 2 is elucidated thereafter. The mildly hierarchical right-chiral neutrino case (including the quasidegenerate possibility) is discussed in an appendix.

Section: Jhep06(2018)085mentioning

confidence: 99%

Section: Jhep06(2018)085mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Consequences of minimal seesaw with complex μτ antisymmetry of neutrinos

Samanta

Roy

Ghosal

2018

“…The idea was first explored in the context of CP symmetry combined with µ − τ reflection symmetry, resulting in the atmospheric mixing angle θ 23 and the Dirac CP phase δ CP both being determined to be maximal, as discussed in [21][22][23][24][25][26][27]. More recently, the phenomenological consequences of imposing both an S 4 family symmetry and a generalised CP symmetry have been investigated in a model-independent way [28][29][30][31][32][33].…”

Section: Jhep12(2014)007mentioning

confidence: 99%

Generalised CP and Δ(6n 2) family symmetry in semi-direct models of leptons

Ding

King

Neder

2014

Abstract:We perform a detailed analysis of ∆(6n 2 ) family symmetry combined with a generalised CP symmetry in the lepton sector, breaking to different remnant symmetries G ν in the neutrino and G l in the charged lepton sector, together with different remnant CP symmetries in each sector. We discuss the resulting mass and mixing predictions for G ν = Z 2 with G l = K 4 , Z p , p > 2 and G ν = K 4 with G l = Z 2 . All cases correspond to the preserved symmetry smaller than the full Klein symmetry, as in the semi-direct approach, leading to predictions which depend on a single undetermined real parameter, which mainly determines the reactor angle. We focus on five phenomenologically allowed cases for which we present the resulting predictions for the PMNS parameters as a function of n, as well as the predictions for neutrinoless double beta decay.

“…refs. [44,45]). But here we simply assume that the µ-τ reflection symmetry does not apply to the charged-lepton sector.…”

Section: Jhep11(2017)135mentioning

confidence: 99%

The μ-τ reflection symmetry of Dirac neutrinos and its breaking effect via quantum corrections

Zhang

Zhu

2017

Given the Dirac neutrino mass term, we explore the constraint conditions which allow the corresponding mass matrix to be invariant under the µ-τ reflection transformation, leading us to the phenomenologically favored predictions θ 23 = π/4 and δ = 3π/2 in the standard parametrization of the 3 × 3 lepton flavor mixing matrix. If such a flavor symmetry is realized at a superhigh energy scale Λ µτ , we investigate how it is spontaneously broken via the one-loop renormalization-group equations (RGEs) running from Λ µτ down to the Fermi scale Λ F . Such quantum corrections to the neutrino masses and flavor mixing parameters are derived, and an analytical link is established between the Jarlskog invariants of CP violation at Λ µτ and Λ F . Some numerical examples are also presented in both the minimal supersymmetric standard model and the type-II two-Higgs-doublet model, to illustrate how the octant of θ 23 , the quadrant of δ and the neutrino mass ordering are correlated with one another as a result of the RGE-induced µ-τ reflection symmetry breaking effects.