scholarly journals On fermion mass hirerachies in MSSM-like quiver models with stringy corrections

Open Physics ◽  
2011 ◽  
Vol 9 (6) ◽  
Author(s):  
Adil Belhaj ◽  
Mohammed Benhamza ◽  
Salah Ennadifi ◽  
Samir Nassiri ◽  
Hassan Saidi
Keyword(s):  
Gauge Symmetry ◽  
Partial Solution ◽  
Fermion Mass ◽  
Neutrino Masses

AbstractUsing instanton effects, we discuss the problem of fermion mass hierarchies in an MSSM-like Type IIA orientifolded model with U(3) × Sp(1) × U(1) × U(1) gauge symmetry obtained from intersecting D6-branes. In the corresponding four-stack quiver, the different scales of the generated superpotential couplings offer a partial solution to fermion mass hierarchies. Using the known data with neutrino masses $$m_{v_\tau } \lesssim 2 eV$$ , we give the magnitudes of the relevant scales.

scholarly journals Anomalous Z′ bosons for anomalous B decays

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Joe Davighi
Keyword(s):  
Gauge Symmetry ◽  
Light Quark ◽  
Z Bosons ◽  
Fermion Mass ◽  
Neutrino Masses ◽  
B Decays ◽  
Quark Masses ◽  
The Standard Model ◽  
Gauge Anomalies ◽  
Lepton Flavour

Abstract Motivated by the intriguing discrepancies in b → sℓℓ transitions, the fermion mass problem, and a desire to preserve the accidental symmetries of the Standard Model (SM), we extend the SM by an anomalous U(1)X gauge symmetry where X = Y3 + a(Lμ− Lτ)/6. The heavy Z′ boson associated with spontaneously breaking U(1)X at the TeV scale mediates the b → sℓℓ anomalies via $$ {\mathcal{O}}_9^{\mu}\sim \frac{1}{\Lambda^2}\left(\overline{s}{\gamma}_{\rho }{P}_Lb\right)\left(\overline{\mu}{\gamma}^{\rho}\mu \right) $$ O 9 μ ~ 1 Λ 2 s ¯ γ ρ P L b μ ¯ γ ρ μ . We show that this model, which features mixed gauge anomalies involving U(1)X and hypercharge, can be made anomaly-free for any a ∈ ℤ by integrating in a pair of charged fermions whose masses naturally reside somewhere between 1 and 30 TeV. The gauge symmetry permits only the third family Yukawas at the renormalisable level, and so the light quark masses and mixings are controlled by accidental U(2)3 flavour symmetries which we assume are minimally broken alongside U(1)X. The lepton sector is not governed by U(2) symmetries, but rather one expects a nearly diagonal charged lepton Yukawa with me,μ « mτ. The model does not explain the hierarchy me « mμ, but it does possess high quality lepton flavour symmetries that are robust to the heavy physics responsible for generating me,μ. We establish the viability of these models by checking agreement with the most important experimental constraints. We comment on how the model could also explain neutrino masses and the muon g − 2.

scholarly journals Neutrino masses along with fermion mass hierarchy

2012 ◽  
Vol 85 (1) ◽  
Author(s):  
Dilip Kumar Ghosh ◽  
R. S. Hundi
Keyword(s):  
Fermion Mass ◽  
Neutrino Masses ◽  
Mass Hierarchy

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 ON FERMION MASS HIERARCHY WITH EXTRA DIMENSIONS

2000 ◽  
Vol 15 (01) ◽  
pp. 29-39 ◽  
Author(s):  
KOICHI YOSHIOKA
Keyword(s):  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Atmospheric Neutrino ◽  
Fermion Mass ◽  
Neutrino Masses ◽  
Mass Hierarchy ◽  
Mixing Angles ◽  
Four Dimensions ◽  
Matter Fields ◽  
Neutrino Masses And Mixings

Recently, various phenomenological implications of the existence of extra space–time dimensions have been investigated. In this letter, we construct a model with realistic fermion mass hierarchy with (large) extra dimensions beyond the usual four dimensions. In this model, it is assumed that some matter fields live in the bulk and the others are confined to our four-dimensional wall. It can naturally reproduce the quark and lepton mass hierarchy and mixing angles without any symmetry arguments. We also discuss some possibilities of obtaining suitable neutrino masses and mixings for the solar and atmospheric neutrino problems.

MASSIVE FERMION AND CHIRAL GAUGE SYMMETRY

1990 ◽  
Vol 05 (31) ◽  
pp. 2607-2613 ◽  
Author(s):  
SINYA AOKI
Keyword(s):  
Gauge Symmetry ◽  
Effective Action ◽  
Gauge Theories ◽  
Opposite Sign ◽  
Chiral Anomaly ◽  
Fermion Mass ◽  
Mass Limit ◽  
Massive Fermion ◽  
Dependent Term ◽  
Mass Dependent

A mass-dependent odd-parity term in the effective action of chiral gauge theories as well as the usual mass-independent chiral anomaly have been shown to exist. In particular, this mass-dependent term is equal to the anomaly with opposite sign in the limit of infinite fermion mass, and therefore no odd-parity term remains in this limit. We also consider the different regularizations which produce the Wess-Zumino term in the infinite fermion mass limit.

scholarly journals NEUTRINO MASSES AND μ TERMS IN A SUPERSYMMETRIC EXTRA U(1) MODEL

2010 ◽  
Vol 25 (21) ◽  
pp. 4033-4053 ◽  
Author(s):  
DAIJIRO SUEMATSU ◽  
TAKASHI TOMA ◽  
TETSURO YOSHIDA
Keyword(s):  
Gauge Symmetry ◽  
Neutrino Oscillation ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrino Mass Matrix ◽  
Neutrino Masses ◽  
A Value

We propose a supersymmetric extra U(1) model, which can generate small neutrino masses and necessary μ terms, simultaneously. Fields including quarks and leptons are embedded in three 27's of E6 in a different way among generations. The model has an extra U(1) gauge symmetry at TeV regions, which has discriminating features from other models studied previously. Since a neutrino mass matrix induced in the model has a constrained texture with limited parameters, it can give a prediction. If we impose neutrino oscillation data to fix those parameters, a value of sin θ13 can be determined. We also discuss several phenomenological features which are discriminated from the ones of the MSSM.

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