Type II seesaw origin of nonzero θ13, δCP and leptogenesis

We discuss the possible origin of nonzero reactor mixing angle θ13 and Dirac CP phase δ CP in the leptonic sector from a combination of type I and type II seesaw mechanisms. Type I seesaw contribution to neutrino mass matrix is of tri-bimaximal (TBM) type which gives rise to vanishing θ13 leaving the Dirac CP phase undetermined. If the Dirac neutrino mass matrix is assumed to take the diagonal charged lepton (CL) type structure, such a TBM type neutrino mass matrix originating from type I seesaw corresponds to real values of Dirac Yukawa couplings in the terms [Formula: see text]. This makes the process of right-handed heavy neutrino decay into a light neutrino and Higgs (N → νH) CP preserving ruling out the possibility of leptogenesis. Here we consider the type II seesaw term as the common origin of nonzero θ13 and δ CP by taking it as a perturbation to the leading order TBM type neutrino mass matrix. First, we numerically fit the type I seesaw term by taking oscillation as well as cosmology data and then compute the predictions for neutrino parameters after the type II seesaw term is introduced. We consider a minimal structure of the type II seesaw term and check whether the predictions for neutrino parameters lie in the 3σ range. We also compute the predictions for baryon asymmetry of the universe by considering type II seesaw term as the only source of CP violation and compare it with the latest cosmology data.

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TEXTURE-ZERO MODEL FOR THE LEPTON MASS MATRICES

Modern Physics Letters A ◽

10.1142/s0217732312501593 ◽

2012 ◽

Vol 27 (28) ◽

pp. 1250159 ◽

Cited By ~ 3

Author(s):

P. M. FERREIRA ◽

L. LAVOURA

Keyword(s):

Mass Spectrum ◽

Neutrino Mass ◽

Mass Matrix ◽

Type I ◽

Mixing Angle ◽

Mass Matrices ◽

Neutrino Mass Spectrum ◽

Texture Zero ◽

Vanishing Elements ◽

Reactor Mixing

We suggest a simple model, based on the type-I seesaw mechanism, for the lepton mass matrices. The model hinges on an Abelian symmetry which leads to mass matrices with some vanishing matrix elements. The model predicts one massless neutrino and Meμ = 0 (M is the effective light-neutrino Majorana mass matrix). We show that these predictions agree with the present experimental data if the neutrino mass spectrum is inverted, i.e. if m3 = 0, provided the Dirac phase δ is very close to maximal (±π/ 2). In the case of a normal neutrino mass spectrum, i.e. when m1 = 0, the agreement of our model with the data is imperfect — the reactor mixing angle θ13 is too small in our model. Minimal leptogenesis is not an option in our model due to the vanishing elements in the Yukawa-coupling matrices.

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Broken scaling neutrino mass matrix and leptogenesis based on A4 modular invariance

Journal of High Energy Physics ◽

10.1007/jhep09(2021)100 ◽

2021 ◽

Vol 2021 (9) ◽

Author(s):

Monal Kashav ◽

Surender Verma

Keyword(s):

Neutrino Mass ◽

Yukawa Coupling ◽

Complex Modulus ◽

Mass Matrix ◽

Neutrino Mass Matrix ◽

Neutrino Masses ◽

Symmetric Model ◽

Type I ◽

Minimal Extension ◽

The Universe

Abstract In this work, we have proposed a modular A4 symmetric model of neutrino mass which, simultaneously, explains observed baryon asymmetry of the Universe (BAU). In minimal extension of the standard model (SM) with two right-handed neutrinos we work in a supersymmetric framework. At Type-I seesaw level, the model predicts scaling in the neutrino mass matrix. In order to have correct low energy phenomenology, we propose two possible scenarios of scale-breaking in the neutrino mass matrix emanating from Type-I seesaw. Scenario-1 is based on the dimension-5 Weinberg operator whereas scenario-2 implements Type-II seesaw via scalar triplet Higgs superfields (∆,$$ \overline{\Delta } $$ ∆ ¯ ). Interestingly, the breaking patterns in both, otherwise dynamically different scenarios, are similar which can be attributed to the same charge assignments of superfields (∆,$$ \overline{\Delta } $$ ∆ ¯ ) and the Higgs superfield Hu under modular A4 symmetry. The breaking is found to be proportional to the Yukawa coupling of modular weight 10 ($$ {Y}_{1,1\prime}^{10} $$ Y 1 , 1 ′ 10 ). We, further, investigates the predictions of the model under scenario-2 (Type-I+II) for neutrino mass, mixings and matter-antimatter asymmetry of the Universe. The model predicts normal hierarchical neutrino masses and provide a robust range (0.05 − 0.08)eV for sum of neutrino masses (Σmi). Lepton number violating 0νββ decay amplitude (Mee) is obtained to lie in the range (0.04 − 0.06)eV. Future 0νββ decay experiments such as NEXT and nEXO shall pose crucial test for the model. Both CP conserving and CP violating solutions are allowed in the model. Interesting correlations are obtained, specially, between Yukawa couplings of modular weight 2 and complex modulus τ. Contrary to $$ {Y}_2^2 $$ Y 2 2 and $$ {Y}_3^2 $$ Y 3 2 , the Yukawa coupling $$ {Y}_1^2 $$ Y 1 2 is found to be insensitive to τ and thus to CP violation because complex modulus τ is the only source of CP violation in the model. We, also, investigate the prediction of the model for BAU. The model exhibit consistent explanation of BAU for right-handed Majorana neutrino mass scale in the range ((1 − 5) × 1013) GeV.

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Connecting leptonic CP violation, lightest neutrino mass and baryon asymmetry through type II seesaw

International Journal of Modern Physics A ◽

10.1142/s0217751x15500451 ◽

2015 ◽

Vol 30 (09) ◽

pp. 1550045 ◽

Cited By ~ 8

Author(s):

Rupam Kalita ◽

Debasish Borah

Keyword(s):

Cp Violation ◽

Neutrino Mass ◽

Mass Matrix ◽

Baryon Asymmetry ◽

Type I ◽

Type Ii ◽

Neutrino Mixing ◽

Mixing Angles ◽

The Universe ◽

Mass Type

We study the possibility of connecting leptonic Dirac CP phase δ, lightest neutrino mass and baryon asymmetry of the universe within the framework of a model where both type I and type II seesaw mechanisms contribute to neutrino mass. Type I seesaw gives rise to Tri-Bimaximal (TBM) type neutrino mixing whereas type II seesaw acts as a correction in order to generate nonzero θ13. We derive the most general form of type II seesaw mass matrix which cannot only give rise to correct neutrino mixing angles but also can generate nontrivial value of δ. Considering both the cases where type II seesaw is subleading and is equally dominant compared to type I seesaw, we correlate the type II seesaw term with δ and lightest neutrino mass. We further constrain the Dirac CP phase δ and hence the type II seesaw mass matrix from the requirement of producing the observed baryon asymmetry through the mechanism of leptogenesis.

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LEPTOGENESIS IN A HYBRID TEXTURE NEUTRINO MASS MODEL

Modern Physics Letters A ◽

10.1142/s0217732310033682 ◽

2010 ◽

Vol 25 (33) ◽

pp. 2837-2848 ◽

Cited By ~ 4

Author(s):

S. DEV ◽

SURENDER VERMA

Keyword(s):

Neutrino Mass ◽

Mass Matrix ◽

Baryon Asymmetry ◽

Neutrino Mass Matrix ◽

Type I ◽

Mass Model ◽

Family Symmetry ◽

Cp Asymmetry ◽

Seesaw Mechanism ◽

The Universe

We investigate the CP asymmetry for a hybrid texture of the neutrino mass matrix predicted by Q8 family symmetry in the context of the type-I seesaw mechanism and examine its consequences for leptogenesis. We, also, calculate the resulting Baryon Asymmetry of the Universe (BAU) for this texture.

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Significance of Broken μ − τ Symmetry in Correlating δ CP , θ 13 , Lightest Neutrino Mass, and Neutrinoless Double Beta Decay 0 ν β β

Advances in High Energy Physics ◽

10.1155/2021/9563917 ◽

2021 ◽

Vol 2021 ◽

pp. 1-23

Author(s):

Gayatri Ghosh

Keyword(s):

Cp Violation ◽

Neutrino Oscillation ◽

Neutrino Mass ◽

Parameter Space ◽

Double Beta Decay ◽

Light Neutrino ◽

Type I ◽

Mixing Angle ◽

Reactor Mixing ◽

The Universe

Leptonic CP violating phase δ CP in the light neutrino sector and leptogenesis via present matter-antimatter asymmetry of the Universe entails each other. Probing CP violation in light neutrino oscillation is one of the challenging tasks today. The reactor mixing angle θ 13 measured in reactor experiments, LBL, and DUNE with high precision in neutrino experiments indicates towards the vast dimensions of scope to detect δ CP . The correlation between leptonic Dirac CPV phase δ CP , reactor mixing angle θ 13 , lightest neutrino mass m 1 , and matter-antimatter asymmetry of the Universe within the framework of μ − τ symmetry breaking assuming the type I seesaw dominance is extensively studied here. Here, a SO(10) GUT model with flavor μ − τ symmetry is considered. In this work, the idea is to link baryogenesis through leptogenesis and the hint of CP violation in the neutrino oscillation data to a breaking of the mu-tau symmetry. Small tiny breaking of the μ − τ symmetry allows a large Dirac CP violating phase in neutrino oscillation which in turn is characterized by awareness of measured value of θ 13 and to provide a hint towards a better understanding of the experimentally observed near-maximal value of ν μ − ν τ mixing angle θ 23 ≃ π / 4 . Precise breaking of the μ − τ symmetry is achieved by adding a 120-plet Higgs to the 10 + 1 2 ¯ 6 -dimensional representation of Higgs. The estimated three-dimensional density parameter space of the lightest neutrino mass m 1 , δ CP , and reactor mixing angle θ 13 is constrained here for the requirement of producing the observed value of baryon asymmetry of the Universe through the mechanism of leptogenesis. Carrying out numerical analysis, the allowed parameter space of m 1 , δ CP , and θ 13 is found out which can produce the observed baryon to photon density ratio of the Universe.

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Two Higgs singlets $A_4$ Flavor Symmetry with Minimal Breaking

Communications in Physics ◽

10.15625/0868-3166/24/2/3946 ◽

2014 ◽

Vol 24 (2) ◽

pp. 113 ◽

Cited By ~ 1

Author(s):

Nguyen Thanh Phong

Keyword(s):

Neutrino Mass ◽

Mass Matrix ◽

Baryon Asymmetry ◽

Neutrino Mass Matrix ◽

Flavor Symmetry ◽

Mixing Angle ◽

Mixing Angles ◽

The Universe

We study the seesaw realization of a $A_4$model with two Higgs singlets. In this model, the mixing angle $\theta_{13}$ and leptogenesis are zero if the components of right handed neutrino mass matrix resulting from the two Higgs singlets are exact degenerate. We then study the minimal breaking of the model by a tiny shift between aforementioned components. This minimal breaking results in deviations of lepton mixing angles from their tri-bimaximal mixing values in which the current experimental value of $\theta_{13}$ can be achieved. Besides, the baryon asymmetry of the Universe is successfully generated through non-zero leptogenesis by the decay of right handed neutrinos.

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NONZERO θ13 FROM THE TRIANGULAR ANSATZ AND LEPTOGENESIS

Modern Physics Letters A ◽

10.1142/s0217732312501519 ◽

2012 ◽

Vol 27 (26) ◽

pp. 1250151 ◽

Cited By ~ 3

Author(s):

H. B. BENAOUM

Keyword(s):

Neutrino Mass ◽

Mass Matrix ◽

Baryon Asymmetry ◽

Neutrino Mass Matrix ◽

Type I ◽

Seesaw Mechanism ◽

Dimensionless Parameters ◽

Dirac Neutrino ◽

The Universe

Recent experiments indicate a departure from the exact tri-bimaximal mixing by measure ring definitive nonzero value of θ13. Within the framework of type I seesaw mechanism, we reconstruct the triangular Dirac neutrino mass matrix from the μ - τ symmetric mass matrix. The deviation from μ - τ symmetry is then parametrized by adding dimensionless parameters yi in the triangular mass matrix. In this parametrization of the neutrino mass matrix, the nonzero value θ13 is controlled by Δy = y4 - y6. We also calculate the resulting leptogenesis and show that the triangular texture can generate the observed baryon asymmetry in the universe via leptogenesis scenario.

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Investigating the Hybrid Textures of Neutrino Mass Matrix for Near Maximal Atmospheric Neutrino Mixing

Advances in High Energy Physics ◽

10.1155/2018/5806743 ◽

2018 ◽

Vol 2018 ◽

pp. 1-16

Author(s):

Madan Singh

Keyword(s):

Neutrino Mass ◽

Mass Matrix ◽

Atmospheric Neutrino ◽

Zero Element ◽

Majorana Neutrino ◽

Neutrino Mixing ◽

Mixing Angle ◽

The Comparative Study ◽

Reactor Mixing ◽

Majorana Neutrino Mass

We have studied that the implication of a large value of the effective Majorana neutrino mass in case of neutrino mass matrices has either two equal elements and one zero element (popularly known as hybrid texture) or two equal cofactors and one zero minor (popularly known as inverse hybrid texture) in the flavor basis. In each of these cases, four out of sixty phenomenologically possible patterns predict near maximal atmospheric neutrino mixing angle in the limit of large effective Majorana neutrino mass. This feature remains irrespective of the experimental data on solar and reactor mixing angles. In addition, we have also performed the comparative study of all the viable cases of hybrid and inverse hybrid textures at 3σ CL.

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