scholarly journals TeV-SCALE TYPE-II SEESAW MODELS AND POSSIBLE COLLIDER SIGNATURES

2008 ◽  
Vol 23 (21) ◽  
pp. 3420-3424 ◽  
Author(s):  
WEI CHAO ◽  
SHU LUO ◽  
ZHI-ZHONG XING ◽  
SHUN ZHOU
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Natural Extension ◽  
Simple Type ◽  
Type Ii ◽  
Neutrino Mixing ◽  
Long Baseline ◽  
Majorana Neutrinos ◽  
Mixing Matrix ◽  
The Right

A natural extension of the standard model to accommodate massive neutrinos is to introduce one Higgs triplet and three right-handed Majorana neutrinos, leading to a 6×6 neutrino mass matrix. We show that three light Majorana neutrinos (i.e., the mass eigenstates of νe, νμ and ντ) are exactly massless, if and only if [Formula: see text] exactly holds in this seesaw model. We propose three simple Type-II seesaw scenarios with broken A4 × U(1)x flavor symmetry to interpret the observed neutrino mass spectrum and neutrino mixing pattern. Such a TeV-scale neutrino model can be tested in two complementary ways: (1) searching for possible collider signatures of lepton number violation induced by the right-handed Majorana neutrinos and doubly-charged Higgs particles; and (2) searching for possible consequences of unitarity violation of the 3 × 3 neutrino mixing matrix in the future long-baseline neutrino oscillation experiments.

scholarly journals THE MINIMAL TYPE-II SEESAW MODEL AND FLAVOR-DEPENDENT LEPTOGENESIS

2008 ◽  
Vol 23 (21) ◽  
pp. 3412-3415
Author(s):  
SHU LUO ◽  
ZHI-ZHONG XING
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Baryon Number ◽  
Majorana Neutrino ◽  
Type Ii ◽  
Neutrino Mixing ◽  
Seesaw Model ◽  
Mixing Matrix ◽  
Current Experimental Data ◽  
Minimal Type

Current experimental data allow the zero value for one neutrino mass, either m1 = 0 or m3 = 0. This observation implies that a realistic neutrino mass texture can be established by starting from the limit (a) m1 = m2 = 0 and m3 ≠ 0 or (b) m1 = m2 ≠ 0 and m3 = 0. In both cases, we may introduce a particular perturbation which ensures the resultant neutrino mixing matrix to be the tri-bimaximal mixing pattern or its viable variations. We find that it is natural to incorporate this kind of neutrino mass matrix in the minimal Type-II seesaw model with only one heavy right-handed Majorana neutrino N. We show that it is possible to account for the cosmological baryon number asymmetry in the m3 = 0 case via thermal leptogenesis, in which the CP-violating asymmetry of N decays is attributed to the electron flavor.

scholarly journals NEUTRINO MASSES, LEPTON FLAVOR MIXING AND LEPTOGENESIS IN THE MINIMAL SEESAW MODEL

2007 ◽  
Vol 16 (01) ◽  
pp. 1-50 ◽  
Author(s):  
WAN-LEI GUO ◽  
ZHI-ZHONG XING ◽  
SHUN ZHOU
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Neutrino Mixing ◽  
Lepton Flavor ◽  
Seesaw Model ◽  
Flavor Mixing ◽  
Majorana Neutrinos

We present a review of neutrino phenomenology in the minimal seesaw model (MSM), an economical and intriguing extension of the Standard Model with only two heavy right-handed Majorana neutrinos. Given current neutrino oscillation data, the MSM can predict the neutrino mass spectrum and constrain the effective masses of the tritium beta decay and the neutrinoless double-beta decay. We outline five distinct schemes to parameterize the neutrino Yukawa-coupling matrix of the MSM. The lepton flavor mixing and baryogenesis via leptogenesis are investigated in some detail by taking account of possible texture zeros of the Dirac neutrino mass matrix. We derive an upper bound on the CP-violating asymmetry in the decay of the lighter right-handed Majorana neutrino. The effects of the renormalization-group evolution on the neutrino mixing parameters are analyzed, and the correlation between the CP-violating phenomena at low and high energies is highlighted. We show that the observed matter-antimatter asymmetry of the Universe can naturally be interpreted through the resonant leptogenesis mechanism at the TeV scale. The lepton-flavor-violating rare decays, such as μ→e+γ, are also discussed in the supersymmetric extension of the MSM.

SYMMETRIES OF NEUTRINO MIXING

2003 ◽  
Vol 18 (22) ◽  
pp. 3957-3970 ◽  
Author(s):  
P. F. HARRISON ◽  
W. G. SCOTT
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Neutrino Mixing ◽  
Natural Representation ◽  
Induced Representation ◽  
Group Matrix ◽  
Class Operator ◽  
Mixing Matrix ◽  
Mass Basis

Encouraged by the phenomenological success of the tri-bimaximal hypothesis, we postulate that the neutrino mass matrix in the lepton flavour basis is an S3 group matrix in the natural representation of S3. This immediately requires one neutrino to be trimaximally mixed, as suggested by the solar neutrino data. We go on to postulate that the charged-lepton mass matrix in the neutrino mass-basis is an S3 class matrix in the natural representation of the S3 class-algebra, leading to exact tri-bimaximal mixing which is compatible with data overall. The above two postulates are mutually consistent, and imply that the neutrino mass matrix in the flavour basis is an S3⊃S2 class operator, in the natural representation of the S3 group (the S2 being associated with mu-tau interchange). Thus the tri-bimaximal mixing matrix is seen to be closely related to the S3 group characters, and may be properly regarded as simply the table of induction coefficients for the [2]×[1]=[3]+[21] induced representation of S3.

scholarly journals NEUTRINO OSCILLATIONS AND LEPTON FLAVOR MIXING

2001 ◽  
Vol 16 (33) ◽  
pp. 2169-2175 ◽  
Author(s):  
KYUNGSIK KANG ◽  
SIN KYU KANG ◽  
C. S. KIM ◽  
SUN MYONG KIM
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Masses ◽  
Input Constraints ◽  
Neutrino Mixing ◽  
Lepton Flavor ◽  
Invariance Violation ◽  
The Family ◽  
Flavor Mixing ◽  
Mixing Matrix

In view of the recent announcement on nonzero neutrino mass from Super-Kamiokande experiment, it would be very timely to investigate all the possible scenarios on masses and mixings of light neutrinos. Recently suggested mass matrix texture for the quark CKM mixing, which can be originated from the family permutation symmetry and its suitable breakings, is assumed for the neutrino mass matrix and determined by the four combinations of solar, atmospheric and LSND neutrino data and cosmological hot dark matter bound as input constraints. The charged-lepton mass matrix is assumed to be diagonal so that the neutrino mixing matrix can be identified directly as the lepton flavor mixing matrix and no CP invariance violation originates from the leptonic sector. The results favor hierarchical patterns for the neutrino masses, which follow from the case when the solar-atmospheric data is used.

scholarly journals NEUTRINO MIXING AND THE DOUBLE TETRAHEDRAL GROUP

2013 ◽  
Vol 28 (29) ◽  
pp. 1350157 ◽  
Author(s):  
YONI BENTOV ◽  
A. ZEE
Keyword(s):  
Group Theory ◽  
Cp Violation ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Double Cover ◽  
Neutrino Mass Matrix ◽  
Two Dimensional ◽  
Neutrino Mixing ◽  
Mixing Matrix ◽  
Relevant Group

In the spirit of a previous study of the tetrahedral group T ≃A4, we discuss a minimalist scheme to derive the neutrino mixing matrix using the double tetrahedral group T′, the double cover of T. The new features are three distinct two-dimensional representations and complex Clebsch–Gordan coefficients, which can result in a geometric source of CP violation in the neutrino mass matrix. In an appendix, we derive explicitly the relevant group theory for the tetrahedral group T and its double cover T′.

scholarly journals TETRAHEDRAL FAMILY SYMMETRY AND THE NEUTRINO MIXING MATRIX

2005 ◽  
Vol 20 (34) ◽  
pp. 2601-2605 ◽  
Author(s):  
ERNEST MA
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Neutrino Mixing ◽  
Symmetry Limit ◽  
Family Symmetry ◽  
Seesaw Mechanism ◽  
Mixing Angles ◽  
Mixing Matrix ◽  
Natural Symmetry

In a new application of the discrete non-Abelian symmetry A4 using the canonical seesaw mechanism, a three-parameter form of the neutrino mass matrix is derived. It predicts the following mixing angles for neutrino oscillations: θ13=0, sin 2θ23=1/2, and sin 2θ12 close, but not exactly equal to 1/3, in one natural symmetry limit.

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

2015 ◽  
Vol 30 (09) ◽  
pp. 1550045 ◽  
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.

scholarly journals THE TYPE-II SINGULAR SEE-SAW MECHANISM

2007 ◽  
Vol 22 (12) ◽  
pp. 2211-2222 ◽  
Author(s):  
K. L. MCDONALD ◽  
B. H. J. MCKELLAR
Keyword(s):  
Mass Matrix ◽  
The Body ◽  
Type Ii ◽  
Neutrino Spectrum ◽  
Majorana Mass ◽  
Mass Matrices ◽  
Majorana Neutrinos ◽  
Neutrino Fluxes ◽  
The Right ◽  
Structure Result

The singular see-saw mechanism is a variation of the see-saw mechanism whereby the right-chiral neutrino Majorana mass matrix is singular. Previous works employing the singular see-saw mechanism have assumed a vanishing left-chiral Majorana mass matrix. We study the neutrino spectrum obtained under a singular see-saw mechanism when the left-chiral neutrinos possess a nonzero Majorana mass matrix. We refer to this as the type-II singular see-saw mechanism. The resulting neutrino spectrum is found to be sensitive to the hierarchy of the Dirac and Majorana mass scales used and we explore the phenomenological consequences of the candidate hierarchies. The compatibility of the resulting spectra with the body of neutrino oscillation data is discussed. It is found that neutrino mass matrices with this structure result in 3+1 or 2+2 neutrino spectra, making it unlikely that this mass matrix structure is realized in nature. If the left-chiral Majorana mass matrix is also singular we show that a type-II singular see-saw mechanism can realize a spectrum of one active-sterile pseudo-Dirac neutrino in conjunction with two active Majorana neutrinos effectively decoupled from the sterile sector. This realizes a scheme discussed in the literature in relation to astrophysical neutrino fluxes.

scholarly journals NONZERO θ13 AND NEUTRINO MASSES FROM MODIFIED NEUTRINO MIXING MATRIX

2012 ◽  
Vol 27 (17) ◽  
pp. 1250091 ◽  
Author(s):  
ASAN DAMANIK
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Daya Bay ◽  
Neutrino Mixing ◽  
Inverted Hierarchy ◽  
Solar Mass ◽  
Double Chooz ◽  
Mass Matrices ◽  
Mixing Matrix

The nonzero and relatively large θ13 have been reported by Daya Bay, T2K, MINOS and Double Chooz Collaborations. In order to accommodate the nonzero θ13, we modified the tribimaximal (TB), bimaxima (BM) and democratic (DC) neutrino mixing matrices. From three modified neutrino mixing matrices, two of them (the modified BM and DC mixing matrices) can give nonzero θ13 which is compatible with the result of the Daya Bay and T2K experiments. The modified TB neutrino mixing matrix predicts the value of θ13 which is greater than the upper bound value of the latest experimental results. By using the modified neutrino mixing matrices and imposing an additional assumption that neutrino mass matrices have two zeros texture, we then obtain the neutrino mass in normal hierarchy when (Mν)22 = (Mν)33 = 0 for the neutrino mass matrix from the modified TB neutrino mixing matrix and (Mν)11 = (Mν)13 = 0 for the neutrino mass matrix from the modified DC neutrino mixing matrix. For these two patterns of neutrino mass matrices, either the atmospheric mass squared difference or the solar mass squared difference can be obtained, but not both of them simultaneously. From four patterns of two zeros texture to be considered on the obtained neutrino mass matrix from the modified BM neutrino mixing matrix, none of them can correctly predict the neutrino mass spectrum (normal or inverted hierarchy).

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