B − L extension of the Standard Model based on Σ(18) symmetry for fermion mass and mixing

2020 ◽  
Vol 35 (27) ◽  
pp. 2050223
Author(s):  
V. V. Vien

In this work, we suggest a renormalizable [Formula: see text] extension of the Standard Model with [Formula: see text] symmetry in which the observed fermion mass and mixing pattern is consistent with the experimental values given in Ref. 1 at the tree-level. The neutrino mass ordering and the tiny neutrino masses are induced by the type-I seesaw mechanism. The effective neutrino mass parameters are predicted to be [Formula: see text], [Formula: see text] for NO and [Formula: see text], [Formula: see text] for IO which are well consistent with the recent experimental data. The quark masses are in good agreement while the quark mixing matrix has a little difference with the experimental data taken from Ref. 1 and the Cabibbo angle [Formula: see text] is related to the model parameter [Formula: see text] by the formula [Formula: see text].

2019 ◽  
Vol 35 (04) ◽  
pp. 2050003 ◽  
Author(s):  
V. V. Vien ◽  
N. V. Soi

We suggest a renormalizable standard model (SM) extension based on [Formula: see text] symmetry which accommodates leptonic mass and mixing parameters with nonzero [Formula: see text] and Dirac CP violating phase. Both normal and inverted neutrino mass ordering as well as the smallness of the active neutrino masses are generated at leading order through type-I seesaw mechanism in which the obtained physical parameters are well consistent with the global fit of neutrino oscillation data [P. F. de Salas et al., Phys. Lett. B 782, 633 (2018)], while the quark masses are in good agreement with the recent experimental data [Particle Data Group (M. Tanabashi et al.), Phys. Rev. D 98, 030001 (2018)]. The model also predicts an effective Majorana neutrino mass parameter of [Formula: see text] for normal hierarchy and [Formula: see text] for inverted hierarchy which are all well below the most current upper limit given [P. F. de Salas et al., Front. Astron. Space Sci. 5, 36 (2018); CUORE Collab. (C. Alduino et al.), Phys. Rev. Lett. 120, 132501 (2018)] and beyond the reach of the present [Formula: see text] decay experiments.


2020 ◽  
Vol 80 (8) ◽  
Author(s):  
V. V. Vien ◽  
H. N. Long ◽  
A. E. Cárcamo Hernández

Abstract We propose a renormalizable $$B-L$$B-L Standard Model (SM) extension based on $$S_3$$S3 symmetry which successfully accommodates the observed fermion mass spectra and flavor mixing patterns as well as the CP violating phases. The small masses for the light active neutrinos are generated through a type I seesaw mechanism. The obtained physical parameters in the lepton sector are well consistent with the global fit of neutrino oscillations (Esteban et al. in J High Energy Phys 01:106, 2019) for both normal and inverted neutrino mass orderings. The model also predicts effective neutrino mass parameters of $${\langle m_{ee}\rangle }= {1.02\times 10^{-2}}\,{\mathrm {eV}},\, m_{\beta }= {1.25}\times 10^{-2}\,{\mathrm {eV}}$$⟨mee⟩=1.02×10-2eV,mβ=1.25×10-2eV for normal hierarchy (NH) and $${\langle m_{ee}\rangle } ={5.03}\times 10^{-2}\, {\mathrm {eV}},\, m_{\beta } ={5.05}\times 10^{-2}\, {\mathrm {eV}}$$⟨mee⟩=5.03×10-2eV,mβ=5.05×10-2eV for inverted hierarchy (IH) which are all well consistent with the future large and ultra-low background liquid scintillator detectors which has been discussed in Ref. (Zhao et al. in Chin Phys C 41(5):053001, 2017) or the limit of the effective neutrino mass can be reached by the planning of future experiments. The model results are consistent with and successfully accommodate the recent experimental values of the physical observables of the quark sector, including the six quark masses, the quark mixing angles and the CP violating phase in the quark sector.


2015 ◽  
Vol 30 (30) ◽  
pp. 1530060
Author(s):  
Hong-Mo Chan ◽  
Sheung Tsun Tsou

Apart from the qualitative features described in Paper I (Ref. 1), the renormalization group equation derived for the rotation of the fermion mass matrices are amenable to quantitative study. The equation depends on a coupling and a fudge factor and, on integration, on 3 integration constants. Its application to data analysis, however, requires the input from experiment of the heaviest generation masses [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] all of which are known, except for [Formula: see text]. Together then with the theta-angle in the QCD action, there are in all 7 real unknown parameters. Determining these 7 parameters by fitting to the experimental values of the masses [Formula: see text], [Formula: see text], [Formula: see text], the CKM elements [Formula: see text], [Formula: see text], and the neutrino oscillation angle [Formula: see text], one can then calculate and compare with experiment the following 12 other quantities [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and the results all agree reasonably well with data, often to within the stringent experimental error now achieved. Counting the predictions not yet measured by experiment, this means that 17 independent parameters of the standard model are now replaced by 7 in the FSM.


2005 ◽  
Vol 20 (36) ◽  
pp. 2767-2774 ◽  
Author(s):  
ERNEST MA

If a family symmetry exists for the quarks and leptons, the Higgs sector is expected to be enlarged to be able to support the transformation properties of this symmetry. There are, however, three possible generic ways (at tree level) of hiding this symmetry in the context of the Standard Model with just one Higgs doublet. All three mechanisms have their natural realizations in the unification symmetry E6 and one in SO (10). An interesting example based on SO (10)×A4 for the neutrino mass matrix is discussed.


2019 ◽  
Vol 34 (25) ◽  
pp. 1950198
Author(s):  
V. V. Vien ◽  
D. P. Khoi

We construct a renormalizable [Formula: see text] model with [Formula: see text] symmetry accommodating the observed pattern of fermion masses and mixings with Dirac CP violation phase. The smallness of the active neutrino masses arises from a combination of type I and type II seesaw mechanisms. Both normal and inverted neutrino mass ordering are viable in our model in which the obtained physical observables of the lepton sector are well consistent with the global fit of neutrino oscillation data [P. F. de Salas et al., Phys. Lett. B 782, 633 (2018)] while the CKM matrix is unity at tree level and the quark masses are in good agreement with the experimental data [Particle Data Group (M. Tanabashi et al.), Phys. Rev. D 98, 030001 (2018)]. Furthermore, the model also predicts an effective Majorana neutrino mass parameter of [Formula: see text] eV for normal hierarchy and [Formula: see text] for inverted hierarchy which are consistent with the constraints given in [P. F. de Salas et al., Phys. Lett. B 782, 633 (2018)].


2021 ◽  
Vol 36 (07) ◽  
pp. 2150047
Author(s):  
V. V. Vien

We propose a renormalizable gauge [Formula: see text] extension of the Standard Model (SM) based on [Formula: see text] symmetry and an auxiliary [Formula: see text] symmetry which can explain the observed quark and lepton masses and mixing angles associated to normal neutrino mass ordering through type-I seesaw mechanism. The relation between the atmospheric mixing angle [Formula: see text] and the effective parameters in neutrino sector is analyzed. Two Majorana phases are predicted to be [Formula: see text] and [Formula: see text] and the model also predicts the effective neutrino mass parameters of [Formula: see text], [Formula: see text] which is well consistent with the planning of future experiments. In the quark sector, the model is predictive since it has ten effective parameters that allow to successfully reproduce the experimental values of the experimental values of the ten physical observables of the quark sector.


2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Michael J. Baker ◽  
Peter Cox ◽  
Raymond R. Volkas

Abstract Precision measurements of the Higgs couplings are, for the first time, directly probing the mechanism of fermion mass generation. The purpose of this work is to determine to what extent these measurements can distinguish between the tree-level mechanism of the Standard Model and the theoretically motivated alternative of radiative mass generation. Focusing on the third-family, we classify the minimal one-loop models and find that they fall into two general classes. By exploring several benchmark models in detail, we demonstrate that a radiative origin for the tau-lepton and bottom-quark masses is consistent with current observations. While future colliders will not be able to rule out a radiative origin, they can probe interesting regions of parameter space.


2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Ning Chen ◽  
Tao Han ◽  
Shuailong Li ◽  
Shufang Su ◽  
Wei Su ◽  
...  

Abstract We explore the extent to which future precision measurements of the Standard Model (SM) observables at the proposed Z-factories and Higgs factories may have impacts on new physics beyond the Standard Model, as illustrated by studying the Type-I Two-Higgs-doublet model (Type-I 2HDM). We include the contributions from the heavy Higgs bosons at the tree-level and at the one-loop level in a full model-parameter space. While only small tan β region is strongly constrained at tree level, the large tan β region gets constrained at loop level due to tan β enhanced tri-Higgs couplings. We perform a multiple variable χ2 fit with non-alignment and non-degenerate masses. We find that the allowed parameter ranges could be tightly constrained by the future Higgs precision measurements, especially for small and large values of tan β. Indirect limits on the masses of heavy Higgs bosons can be obtained, which can be complementary to the direct searches of the heavy Higgs bosons at hadron colliders. We also find that the expected accuracies at the Z-pole and at a Higgs factory are quite complementary in constraining mass splittings of heavy Higgs bosons. The typical results are | cos(β − α)| < 0.05, |∆mΦ| < 200 GeV, and tan β ≳ 0.3. The reaches from CEPC, Fcc-ee and ILC are also compared, for both Higgs and Z-pole precision measurements. Comparing to the Type-II 2HDM, the 95% C.L. allowed range of cos(β − α) is larger, especially for large values of tan β.


2016 ◽  
Vol 31 (25) ◽  
pp. 1650142 ◽  
Author(s):  
Guillermo Palacio

We study the neutrino mass generation in the [Formula: see text] electroweak extension of the Standard Model by considering nonrenormalizable dimension 5 effective operators. It is shown that there exist two topologies for the realizations of such an operator at the tree-level and for one of the three-family models the neutrino phenomenology is explored after extending its particle content with an [Formula: see text] fermion singlet and a scalar decuplet. Constraints in the available parameters space of the model are partially discussed.


2018 ◽  
Vol 33 (26) ◽  
pp. 1850152 ◽  
Author(s):  
Jian-Yong Cen ◽  
Jung-Hsin Chen ◽  
Xiao-Gang He ◽  
Jhih-Ying Su

In the Standard Model (SM), the [Formula: see text] parameter is equal to 1 and the ratio [Formula: see text] of Higgs [Formula: see text] and Higgs [Formula: see text] is also equal to 1 at the tree level. When going beyond the SM with more than one type of Higgs representations, these quantities may be different from the SM predictions which can provide crucial information about new physics. There may also exist a certain charged Higgs [Formula: see text] decays into a [Formula: see text] and a [Formula: see text]. Imposing a custodial symmetry can force the parameter [Formula: see text] to be equal to 1 with certain predictions for [Formula: see text] and [Formula: see text]. However, imposing [Formula: see text] without custodial symmetry may have different predictions. We show how differences arise and how to use experimental data to obtain information about the underlying physics in a model with the SM, plus a real and a complex [Formula: see text] triplet.


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