Neutrino mass matrices from two zero 3 × 2 Yukawa textures and minimal d = 5 entries

Abstract

Aiming to relate leptonic CP violating phase δ to the cosmological CP asymmetry, we study the extension of MSSM by two quasi-degenerate (strictly degenerate at tree level) righthanded neutrinos and consider all possible two texture zero 3 × 2 Yukawa matrices plus one ∆L = 2 dimension five (d = 5) operator contributing to the light neutrino mass matrix. We classify all experimentally viable mass matrices, leading to several predictions, and analytically derive predictive relations. We also relate the CP violating δ phase to the CP phase of the thermal leptogenesis.

Calculable cosmological CP violation and resonant leptogenesis

“…As was shown in [15], this could lead to the successful and predictive neutrino sectors. With the addition of this d= 5 operator, the results obtained above can remain intact.…”

“…All textures, within such setup, giving experimentally viable neutrino mass matrices have been studied in great details. As turned out [15], some of them together with successful neutrino sector give interesting predictions and allow to calculate cosmological CP phase in terms of the neutrino CP phase δ.…”

“…[6]. This approach enables one to relate the CP violating phase δ (appearing in the neutrino oscillations) with the cosmological CP asymmetry [6][7][8][9][10][11][12][13][14][15]. Especially attractive looks the setup with two (or more) quasi-degenerate RHN's [9][10][11][12]15] because, besides the further reduction of the model parameter number, it offers the possibility for resonant leptogenesis [16][17][18] (for recent discussions on resonant leptogenesis see [19][20][21][22]).…”

“…As turns out, due to very limited number of parameters, these type of models are either disfavored by the current data [1] or do not generate enough amount of the baryon asymmetry. In order to circumvent this obstacle, in a recent work [15] the setup with two degenerate RHN's and two texture zero 3 × 2 Dirac type Yukawa couplings augmented with a single ∆L = 2 lepton number violating d= 5 operator has been investigated. All textures, within such setup, giving experimentally viable neutrino mass matrices have been studied in great details.…”

“…Inclusion of such terms does not alter RG studies and results mentioned above are robust. For demonstrative purposes we pick up one of the viable models of [15]. That is concrete neutrino texture zero mass matrix (referred to as the texture P 1 ), which emerges via integration of two (quasi) degenerate RHNs and single ∆L = 2, d= 5 operator.…”