scholarly journals PREDICTIONS FROM NON-TRIVIAL QUARK-LEPTON COMPLEMENTARITY

2007 ◽  
Vol 22 (31) ◽  
pp. 5860-5874 ◽  
Author(s):  
MARCO PICARIELLO ◽  
BHAG C. CHAUHAN ◽  
JOÃO PULIDO ◽  
EMILIO TORRENTE-LUJAN
Keyword(s):  
Low Energy ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Dirac Neutrino ◽  
Yukawa Couplings ◽  
Energy Neutrino ◽  
The Matrix ◽  
Lepton Decays

The complementarity between the quark and lepton mixing matrices is shown to provide robust predictions. We obtain these predictions by first showing that the matrix VM, product of the quark (CKM) and lepton (PMNS) mixing matrices, may have a zero (1,3) entry which is favored by experimental data. We obtain that any theoretical model with a vanishing (1,3) entry of VM that is in agreement with quark data, solar, and atmospheric mixing angle leads to [Formula: see text]. This value is consistent with the present 90% CL experimental upper limit. We also investigate the prediction on the lepton phases. We show that the actual evidence, under the only assumption that the correlation matrix VM product of CKM and PMNS has a zero in the entry (1, 3), gives us a prediction for the three CP-violating invariants J, S1, and S2. A better determination of the lepton mixing angles will give stronger prediction for the CP-violating invariants in the lepton sector. These will be tested in the next generation experiments. Finally we compute the effect of non diagonal neutrino mass in li → ljγ in SUSY theories with non trivial Quark-Lepton complementarity and a flavor symmetry. The Quark-Lepton complementarity and the flavor symmetry strongly constrain the theory and we obtain a clear prediction for the contribution to μ → eγ and the τ decays τ → eγ and τ → μγ. If the Dirac neutrino Yukawa couplings are degenerate but the low energy neutrino masses are not degenerate, then the lepton decays are related among them by the VM entries. On the other hand, if the Dirac neutrino Yukawa couplings are hierarchical or the low energy neutrino masses are degenerate, then the prediction for the lepton decays comes from the CKM hierarchy.

scholarly journals Predictions forμ→eγin Supersymmetry from Nontrivial Quark-Lepton Complementarity and Flavor Symmetry

2007 ◽  
Vol 2007 ◽  
pp. 1-17 ◽  
Author(s):  
Marco Picariello
Keyword(s):  
Experimental Data ◽  
Correlation Matrix ◽  
Low Energy ◽  
The Other ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Dirac Neutrino ◽  
Yukawa Couplings ◽  
Energy Neutrino ◽  
Lepton Decays

We compute the effect of nondiagonal neutrino mass inli→ljγin Supersymmetry (SUSY) theories with nontrivial quark-lepton complementarity and a flavor symmetry. The correlation matrixVM=UCKMUPMNSis such that its (1,3) entry, as preferred by the present experimental data, is zero. We do not assume thatVMis bimaximal. Quark-lepton complementarity and the flavor symmetry strongly constrain the theory and we obtain a clear prediction for the contribution toμ→eγand theτdecaysτ→eγandτ→μγ. If the Dirac neutrino Yukawa couplings are degenerate but the low-energy neutrino masses are not degenerate, then the lepton decays are related among them by theVMentries. On the other hand, if the Dirac neutrino Yukawa couplings are hierarchical or the low-energy neutrino masses are degenerate, then the prediction for the lepton decays comes from theUCKMhierarchy.

scholarly journals Running of low-energy neutrino masses, mixing angles and CP violation

2005 ◽  
Vol 631 (1-2) ◽  
pp. 32-41 ◽  
Author(s):  
John Ellis ◽  
Andi Hektor ◽  
Mario Kadastik ◽  
Kristjan Kannike ◽  
Martti Raidal
Keyword(s):  
Cp Violation ◽  
Low Energy ◽  
Neutrino Masses ◽  
Mixing Angles ◽  
Energy Neutrino

scholarly journals THE PROBLEM OF NEUTRINO MASSES IN EXTENSIONS OF THE STANDARD MODEL

2001 ◽  
Vol 16 (32) ◽  
pp. 5101-5199 ◽  
Author(s):  
ISABELLA MASINA
Keyword(s):  
Proton Decay ◽  
Fine Tuning ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Mixing Angle ◽  
Grand Unified Theories ◽  
Triplet Splitting ◽  
Fermion Masses ◽  
The Standard Model ◽  
Neutrino Masses And Mixings

We review the problem of neutrino masses and mixings in the context of grand unified theories. After a brief summary of the present experimental status of neutrino physics, we describe how the see-saw mechanism can automatically account for the large atmospheric mixing angle. We provide two specific examples where this possibility is realized by means of a flavor symmetry. We then review in some detail the various severe problems which plague minimal GUT models (like the doublet–triplet splitting and proton-decay) and which force us to investigate the possibility of constructing more elaborate but realistic models. We then show an example of a quasirealistic SUSY SU(5) model which, by exploiting the crucial presence of an Abelian flavor symmetry, does not require any fine-tuning and predicts a satisfactory phenomenology with respect to coupling unification, fermion masses and mixings and bounds from proton decay.

scholarly journals Fermion mass and mixing in a low-scale seesaw model based on the S4 flavor symmetry

2019 ◽  
Vol 2019 (11) ◽  
Author(s):  
V V Vien ◽  
H N Long ◽  
A E Cárcamo Hernández
Keyword(s):  
Low Energy ◽  
Spontaneous Breaking ◽  
Fermion Mass ◽  
Recent Experimental Data ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Seesaw Model ◽  
Mixing Parameters ◽  
The Masses ◽  
Good Agreement

Abstract We construct a low-scale seesaw model to generate the masses of active neutrinos based on $S_4$ flavor symmetry supplemented by the $Z_2 \times Z_3 \times Z_4 \times Z_{14}\times U(1)_L$ group, capable of reproducing the low-energy Standard Model (SM) fermion flavor data. The masses of the SM fermions and the fermionic mixing parameters are generated from a Froggatt–Nielsen mechanism after spontaneous breaking of the $S_4\times Z_2 \times Z_3 \times Z_4 \times Z_{14}\times U(1)_L$ group. The obtained values for the physical observables of the quark and lepton sectors are in good agreement with the most recent experimental data. The leptonic Dirac CP-violating phase $\delta _\mathrm{CP}$ is predicted to be $259.579^\circ$ and the predictions for the absolute neutrino masses in the model can also saturate the recent constraints.

scholarly journals A KIND OF PREDICTION FROM STRING PHENOMENOLOGY: EXTRA MATTER AT LOW ENERGY

2007 ◽  
Vol 22 (14) ◽  
pp. 989-1003 ◽  
Author(s):  
CARLOS MUÑOZ
Keyword(s):  
Potential Problem ◽  
Low Energy ◽  
Mixing Angles ◽  
Yukawa Couplings ◽  
Problem Finding ◽  
String Phenomenology ◽  
Fermion Masses ◽  
Interesting Pattern ◽  
Low Energies ◽  
Crucial Ingredient

We review the possibility that the Supersymmetric Standard Model arises from orbifold constructions of the E8×E8 Heterotic Superstring, and the phenomenological properties that such a model should have. In particular, trying to solve the discrepancy between the unification scale predicted by the Heterotic Superstring (≈g GUT × 5.27 × 1017 GeV ) and the value deduced from LEP experiments (≈2 × 1016 GeV ), we will predict the presence at low energies of three families of Higgses and vector-like colour triplets. Our approach relies on the Fayet–Iliopoulos breaking, and this is also a crucial ingredient, together with having three Higgs families, to obtain in these models an interesting pattern of fermion masses and mixing angles at the renormalizable level. Namely, after the gauge breaking some physical particles appear combined with other states, and the Yukawa couplings are modified in a well-controlled way. On the other hand, dangerous flavour-changing neutral currents may appear when fermions of a given charge receive their mass through couplings with several Higgs doublets. We will address this potential problem, finding that viable scenarios can be obtained for a reasonable light Higgs spectrum.

Texture zero mass matrices and flavor mixing of quarks and leptons

2015 ◽  
Vol 30 (28) ◽  
pp. 1550138 ◽  
Author(s):  
Harald Fritzsch
Keyword(s):  
Experimental Data ◽  
Neutrino Masses ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Zero Mass ◽  
Fermion Masses ◽  
Mass Matrices ◽  
Flavor Mixing ◽  
Texture Zero ◽  
The Masses

We discuss mass matrices with four texture zeros for the quarks and leptons. The three mixing angles for the quarks and leptons are functions of the fermion masses. The results agree with the experimental data. The ratio of the masses of the first two neutrinos is given by the solar mixing angle. The neutrino masses are calculated: [Formula: see text], [Formula: see text] and [Formula: see text].

scholarly journals NEUTRINO PHYSICS WITH SMALL EXTRA DIMENSIONS

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 704-708 ◽  
Author(s):  
MATTHIAS NEUBERT
Keyword(s):  
Neutrino Physics ◽  
Gravity Model ◽  
Extra Dimensions ◽  
Zero Mode ◽  
Neutrino Masses ◽  
Mixing Angles ◽  
Dirac Neutrino ◽  
The Right ◽  
Fermion Zero Mode

We study neutrino physics in the context of the localized gravity model with non-factorizable metric proposed by Randall and Sundrum. Identifying the right-handed neutrino with a bulk fermion zero mode, which can be localized on the "hidden" 3-brane in the Randall-Sundrum model, we obtain naturally small Dirac neutrino masses with-out invoking a see-saw mechanism. Our model predicts a strong hierarchy of neutrino masses and generically large mixing angles.

Neutrino Masses and Mixing

2003 ◽  
Vol 214 ◽  
pp. 347-356
Author(s):  
Yoji Totsuka
Keyword(s):  
Neutrino Oscillations ◽  
Solar And Atmospheric Neutrinos ◽  
Convincing Evidence ◽  
Neutrino Masses ◽  
Atmospheric Neutrinos ◽  
Mixing Angle ◽  
Mixing Angles ◽  
The One ◽  
Quark Flavors

Recent results on neutrino masses and mixing are presented. There is convincing evidence for nonzero but tiny masses of at least two flavor neutrinos, based on two types of neutrino oscillations, solar and atmospheric neutrinos. The large mixing angle between first and second flavors and also the one between the second and third flavors were found, quite contrary to small mixing angles among quark flavors, and pose a new mystery.

scholarly journals SUPERSTRING MODELS CHALLENGED BY RARE PROCESSES

1987 ◽  
Vol 02 (03) ◽  
pp. 831-890 ◽  
Author(s):  
B. A. CAMPBELL ◽  
J. ELLIS ◽  
K. ENQVIST ◽  
M. K. GAILLARD ◽  
D. V. NANOPOULOS
Keyword(s):  
Upper Bounds ◽  
Low Energy ◽  
Neutrino Masses ◽  
Dynamical Models ◽  
Gauge Bosons ◽  
Yukawa Couplings ◽  
Flavor Changing ◽  
The Standard Model ◽  
New Interactions ◽  
Matter Fields

Superstring models compactified on Calabi–Yau manifolds contain additional matter fields and gauge bosons beyond those in the Standard Model. The new matter and gauge couplings would make additional contributions to conventional electroweak processes, generate extra flavor-changing neutral interactions, and mediate new interactions leading to proton decay and neutrino masses. We use the phenomenological constraints on such effects to derive upper bounds on Yukawa couplings in low-energy dynamical models inspired by the superstring. We draw attention to the processes which give the best bounds on new Yukawa couplings, and which are those where novel superstring effects might first appear as experimental sensitivity is improved. Our bounds are not sufficient to exclude most superstring models with additional light particles, but do suggest that some couplings are too small to realize certain scenarios for symmetry breaking by radiative corrections.

scholarly journals Relating lepton mixing angles with lepton mass hierarchy

2016 ◽  
Vol 31 (04n05) ◽  
pp. 1650002
Author(s):  
Debasish Borah
Keyword(s):  
Neutrino Mass ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Neutrino Masses ◽  
Mass Hierarchy ◽  
Mixing Angle ◽  
Mixing Angles ◽  
Mass Matrices ◽  
Model Independent ◽  
The Difference

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.

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