scholarly journals UNIVERSALITY OF QUARK–LEPTON MASS MATRIX

2013 ◽  
Vol 28 (08) ◽  
pp. 1350017 ◽  
Author(s):  
TAKESHI FUKUYAMA ◽  
HIROYUKI NISHIURA

The recently observed lepton mixing angle θ13 of the MNS mixing matrix is well incorporated in a universal mixing hypothesis between quark and lepton sectors. This hypothesis asserts that, in the charged lepton diagonal base, all other mass matrices for up- and down-type quarks and light neutrinos are diagonalized by the same unitary matrix except for the phase elements. It is expressed as V CKM = U MNS (δ′)†PU MNS (δ) for quark mixing matrix V CKM and lepton mixing matrix U MNS (δ) in the phenomenological level. Here P is a diagonal phase mass matrix. δ′ is a slightly different phase parameter from the Dirac CP-violating phase δ = 1.1π (best fit) in the MNS lepton mixing matrix.

2011 ◽  
Vol 26 (09) ◽  
pp. 661-667 ◽  
Author(s):  
HIROYUKI NISHIURA ◽  
TAKESHI FUKUYAMA

We propose a universal mixing hypothesis between quark and lepton sectors at high energy scale (probably GUT scale) where quark–lepton universality holds. Namely in the charged lepton diagonal base, all the other mass matrices for up and down quarks and neutrinos are diagonalized by the same unitary matrix except for the phase elements. Thanks to this hypothesis, the observed values of the Cabibbo–Kobayashi–Maskawa (CKM) quark mixing matrix and the mixing angles θ12 and θ23 in the Maki–Nakagawa–Sakata (MNS) lepton mixing matrix can predict the unknown magnitudes of the mixing angle θ13 and of the CP violating Dirac phase δ in the MNS matrix. Their allowed regions are rather narrow, 0.036 < sin θ13 < 0.048 and 6° < δ < 12°.


2014 ◽  
Vol 29 (33) ◽  
pp. 1450179
Author(s):  
G. K. Leontaris ◽  
N. D. Vlachos

We investigate the possibility of expressing the charged leptons and neutrino mass matrices as linear combinations of elements of a single finite group. Constraints imposed on the resulting mixing matrix by current data restrict the group types, but allow a nonzero value for the θ13 mixing angle.


1992 ◽  
Vol 07 (25) ◽  
pp. 6357-6370 ◽  
Author(s):  
ROBERT E. SHROCK

We study an ansatz for the quark mass matrix in which all of the nondiagonal entries are nonzero, but which still allows the quark mixing angles to be calculated in terms of ratios of quark masses and certain phases. Analytic calculations of the orthogonal rotation matrices in the up and down quark sectors and the resultant observed quark mixing matrix are presented. Comparison with experimental data is given.


2013 ◽  
Vol 28 (31) ◽  
pp. 1350131 ◽  
Author(s):  
SRINU GOLLU ◽  
K. N. DEEPTHI ◽  
R. MOHANTA

The recent results from Daya Bay and RENO reactor neutrino experiments have firmly established that the smallest reactor mixing angle θ13 is nonvanishing at the 5 σ level, with a relatively large value, i.e. θ13 ≈ 9°. Using the fact that the neutrino mixing matrix can be represented as [Formula: see text], where Ul and Uν result from the diagonalization of the charged lepton and neutrino mass matrices and Pν is a diagonal matrix containing the Majorana phases and assuming the tri-bimaximal (TBM) form for Uν, we investigate the possibility of accounting for the large reactor mixing angle due to the corrections of the charged lepton mixing matrix. The form of Ul is assumed to be that of CKM mixing matrix of the quark sector. We find that with this modification it is possible to accommodate the large observed reactor mixing angle θ13. We also study the implications of such corrections on the other phenomenological observables.


2016 ◽  
Vol 31 (04n05) ◽  
pp. 1650002
Author(s):  
Debasish Borah

We revisit the possibility of relating lepton mixing angles with lepton mass hierarchies in a model-independent way. Guided by the existence of such relations in the quark sector, we first consider all the mixing angles, both in charged lepton and neutrino sectors to be related to the respective mass ratios. This allows us to calculate the leptonic mixing angles observed in neutrino oscillations as functions of the lightest neutrino mass. We show that for both normal and inverted hierarchical neutrino masses, this scenario does not give rise to correct leptonic mixing angles. We then show that correct leptonic mixing angles can be generated with normal hierarchical neutrino masses if the relation between mixing angle and mass ratio is restricted to 1–2 and 1–3 mixing in both charged lepton and neutrino sectors leaving the 2–3 mixing angles as free parameters. We then restrict the lightest neutrino mass as well as the difference between 2–3 mixing angles in charged lepton and neutrino sectors from the requirement of producing correct leptonic mixing angles. We constrain the lightest neutrino mass to be around 0.002 eV and leptonic Dirac CP phase [Formula: see text] such that [Formula: see text]. We also construct the leptonic mass matrices in terms of 2–3 mixing angles and lightest neutrino mass and briefly comment on the possibility of realizing texture zeros in the neutrino mass matrix.


2007 ◽  
Vol 16 (05) ◽  
pp. 1395-1403
Author(s):  
KOICHI MATSUDA ◽  
TAKESHI FUKUYAMA ◽  
HIROYUKI NISHIURA

We study the universal quark and lepton mass matrices in the framework of SO (10) GUT. Namely, all the mass matrices have common zero texture in our model. Furthermore, we set a strict restriction from SO (10) GUT on the mass matrices. We find that good fittings to the CKM quark mixing matrix are obtained and this model naturally derives the bi-large mixings in the lepton sector.


2013 ◽  
Vol 28 (24) ◽  
pp. 1350118 ◽  
Author(s):  
BISWAJIT ADHIKARY ◽  
AMBAR GHOSAL ◽  
PROBIR ROY

Within the type-I seesaw and in the basis where charged lepton and heavy neutrino mass matrices are real and diagonal, μτ symmetric four and three zero neutrino Yukawa textures are perturbed by lowest order μτ symmetry breaking terms. These perturbations are taken to be the most general ones for those textures. For quite small values of those symmetry breaking parameters, permitting a lowest order analysis, current best-fit ranges of neutrino mass squared differences and mixing angles are shown to be accommodable, including a value of θ13 in the observed range, provided all the light neutrinos have an inverted mass ordering.


2013 ◽  
Vol 28 (39) ◽  
pp. 1350184
Author(s):  
RENATA JORA ◽  
JOSEPH SCHECHTER ◽  
M. NAEEM SHAHID

We obtain analytical formulas which connect the neutrino masses and the leptonic mixing matrix with the entries in the mass matrix for the approximation in which the charged lepton mixing matrix is the unit matrix. We also extract the CP violation phase and determine the conditions in which this is present.


2005 ◽  
Vol 20 (16) ◽  
pp. 1217-1225 ◽  
Author(s):  
LUÍS LAVOURA ◽  
ERNEST MA

We propose two simple models for the quark mass matrices which may be implemented through an S3×Z2 symmetry in a supersymmetric context. Each model has eight parameters and, therefore, makes two independent predictions for the quark mixing matrix. The first model predicts [Formula: see text] and [Formula: see text]. The second model, in which the forms of the up-type-quark and down-type-quark mass matrices are interchanged relative to the first one, predicts |Vub/Vcb|~0.11 and |Vtd/Vts|~0.33. Both models have sin 2β~0.5.


2012 ◽  
Vol 27 (28) ◽  
pp. 1250159 ◽  
Author(s):  
P. M. FERREIRA ◽  
L. LAVOURA

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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