scholarly journals Fermion spectrum and $$g-2$$ anomalies in a low scale 3-3-1 model

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
A. E. Cárcamo Hernández ◽  
Yocelyne Hidalgo Velásquez ◽  
Sergey Kovalenko ◽  
H. N. Long ◽  
Nicolás A. Pérez-Julve ◽  
...  
Keyword(s):  
First Generation ◽  
Dipole Moments ◽  
Tree Level ◽  
Fermion Mass ◽  
Seesaw Mechanism ◽  
Strange Quarks ◽  
Loop Level ◽  
Renormalizable Theory ◽  
Experimental Values ◽  
The Masses

AbstractWe propose a renormalizable theory based on the $$SU(3)_C\times SU(3)_L\times U(1)_X$$ S U ( 3 ) C × S U ( 3 ) L × U ( 1 ) X gauge symmetry, supplemented by the spontaneously broken $$U(1)_{L_g}$$ U ( 1 ) L g global lepton number symmetry and the $$S_3 \times Z_2 $$ S 3 × Z 2 discrete group, which successfully describes the observed SM fermion mass and mixing hierarchy. In our model the top and exotic quarks get tree level masses, whereas the bottom, charm and strange quarks as well as the tau and muon leptons obtain their masses from a tree level Universal seesaw mechanism thanks to their mixing with charged exotic vector like fermions. The masses for the first generation SM charged fermions are generated from a radiative seesaw mechanism at one loop level. The light active neutrino masses are produced from a loop level radiative seesaw mechanism. Our model successfully accommodates the experimental values for electron and muon anomalous magnetic dipole moments.

scholarly journals Fermion mass hierarchy and g − 2 anomalies in an extended 3HDM Model

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
A. E. Cárcamo Hernández ◽  
Sergey Kovalenko ◽  
M. Maniatis ◽  
Ivan Schmidt
Keyword(s):  
Magnetic Moments ◽  
Higgs Doublet ◽  
Tree Level ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Strange Quarks ◽  
Lepton Flavor ◽  
Fermion Masses ◽  
Dark Matter Relic Density ◽  
The Masses

Abstract We propose an extension of the three-Higgs-doublet model (3HDM), where the Standard Model (SM) particle content is enlarged by the inclusion of two inert SU2L scalar doublets, three inert and two active electrically neutral gauge singlet scalars, charged vector like fermions and Majorana neutrinos. These additional particles are introduced to generate the SM fermion mass hierarchy from a sequential loop suppression mechanism. In our model the top and exotic fermion masses appear at tree level, whereas the remaining fermions get their masses radiatively. Specifically, bottom, charm, tau and muon masses appear at 1-loop; the masses for the light up, down and strange quarks as well as for the electron at 2-loop and masses for the light active neutrinos at 3-loop. Our model successfully accounts for SM fermion masses and mixings and accommodates the observed Dark Matter relic density, the electron and muon anomalous magnetic moments, as well the constraints arising from charged Lepton Flavor Violating (LFV) processes. The proposed model predicts charged LFV decays within the reach of forthcoming experiments.

scholarly journals The framed Standard Model (II) — A first test against experiment

2015 ◽  
Vol 30 (30) ◽  
pp. 1530060
Author(s):  
Hong-Mo Chan ◽  
Sheung Tsun Tsou
Keyword(s):  
Standard Model ◽  
Renormalization Group Equation ◽  
Fermion Mass ◽  
Group Equation ◽  
Unknown Parameters ◽  
Mass Matrices ◽  
The Standard Model ◽  
Experimental Values ◽  
The Masses ◽  
Independent Parameters

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.

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
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Neutrino Mass ◽  
Tree Level ◽  
Fermion Mass ◽  
Recent Experimental Data ◽  
Type I ◽  
Quark Masses ◽  
The Standard Model ◽  
Experimental Values

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].

scholarly journals Simplicity of AdS supergravity at one loop

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Luis F. Alday ◽  
Xinan Zhou
Keyword(s):  
Closed Form ◽  
Conformal Symmetry ◽  
Flat Space ◽  
Tree Level ◽  
Loop Level ◽  
Level Data ◽  
Space Limit ◽  
Loop Amplitude

Abstract We demonstrate the simplicity of AdS5× S5 IIB supergravity at one loop level, by studying non-planar holographic four-point correlators in Mellin space. We develop a systematic algorithm for constructing one-loop Mellin amplitudes from the tree-level data, and obtain a simple closed form answer for the $$ \left\langle {\mathcal{O}}_2^{SG}{\mathcal{O}}_2^{SG}{\mathcal{O}}_p^{SG}{\mathcal{O}}_p^{SG}\right\rangle $$ O 2 SG O 2 SG O p SG O p SG correlators. The structure of this expression is remarkably simple, containing only simultaneous poles in the Mellin variables. We also study the flat space limit of the Mellin amplitudes, which reproduces precisely the IIB supergravity one-loop amplitude in ten dimensions. Our results provide nontrivial evidence for the persistence of the hidden conformal symmetry at one loop.

scholarly journals Electroweak SU(2)L × U(1)Y model with strong spontaneously fermion-mass-generating gauge dynamics

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Petr Beneš ◽  
Jiří Hošek ◽  
Adam Smetana
Keyword(s):  
Chiral Symmetry Breaking ◽  
Axial Vector ◽  
Higgs Sector ◽  
Dyson Equation ◽  
Mass Splitting ◽  
Fermion Mass ◽  
Goldstone Bosons ◽  
The Standard Model ◽  
Exploratory Stage ◽  
The Masses

Abstract Higgs sector of the Standard model (SM) is replaced by quantum flavor dynamics (QFD), the gauged flavor SU(3)f symmetry with scale Λ. Anomaly freedom requires addition of three νR. The approximate QFD Schwinger-Dyson equation for the Euclidean infrared fermion self-energies Σf(p2) has the spontaneous-chiral-symmetry-breaking solutions ideal for seesaw: (1) Σf(p2) = $$ {M}_{fR}^2/p $$ M fR 2 / p where three Majorana masses MfR of νfR are of order Λ. (2) Σf(p2) = $$ {m}_f^2/p $$ m f 2 / p where three Dirac masses mf = m(0)1 + m(3)λ3 + m(8)λ8 of SM fermions are exponentially suppressed w.r.t. Λ, and degenerate for all SM fermions in f. (1) MfR break SU(3)f symmetry completely; m(3), m(8) superimpose the tiny breaking to U(1) × U(1). All flavor gluons thus acquire self-consistently the masses ∼ Λ. (2) All mf break the electroweak SU(2)L × U(1)Y to U(1)em. Symmetry partners of the composite Nambu-Goldstone bosons are the genuine Higgs particles: (1) three νR-composed Higgses χi with masses ∼ Λ. (2) Two new SM-fermion-composed Higgses h3, h8 with masses ∼ m(3), m(8), respectively. (3) The SM-like SM-fermion-composed Higgs h with mass ∼ m(0), the effective Fermi scale. Σf(p2)-dependent vertices in the electroweak Ward-Takahashi identities imply: the axial-vector ones give rise to the W and Z masses at Fermi scale. The polar-vector ones give rise to the fermion mass splitting in f. At the present exploratory stage the splitting comes out unrealistic.

Experimental and computed dipole moments in donor–bridge–acceptor systems with p-phenylene and p-carboranediyl bridges

2009 ◽  
Vol 74 (1) ◽  
pp. 131-146 ◽  
Author(s):  
Ladislav Drož ◽  
Mark A. Fox ◽  
Drahomír Hnyk ◽  
Paul J. Low ◽  
J. A. Hugh MacBride ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Dipole Moments ◽  
Electronic Effects ◽  
Electronic Interactions ◽  
Donor And Acceptor ◽  
Homo And Lumo ◽  
Pull Systems ◽  
The Difference ◽  
Experimental Values ◽  
2D And 3D

Dipole moments were measured for a series of substituted benzenes, biphenyls, terphenyls, C-monoaryl- and C,C′-diaryl-p-carboranes. For the donor–bridge–acceptor systems, Me2N–X–NO2, where X is 1,4-phenylene, biphenyl-4,4′-diyl, terphenyl and 1,4-C6H4-p-CB10H10C-1,4-C6H4, the measured interaction dipole moments are 1.36, 0.74, 0.51 and 0.00 D, respectively. The magnitude of the dipole moment reflects the ability of the bridge to transmit electronic effects between donor and acceptor groups. Thus, whilst the 1,4-phenylene bridges allow moderate electronic interactions between the remote groups, the p-carboranediyl unit is less efficient as a conduit for electronic effects. Averaged dipole moments computed at the DFT (B3LYP/6-31G*) level of theory from two distinct molecular conformers are in good agreement with the experimental values. Examination of the calculated electronic structures provides insight into the nature of the interactions between the donor and acceptor moieties through these 2D and 3D aromatic bridges. The most significant cooperative effect of the bridge on the dipole moment occurs in systems where there is some overlap between the HOMO and LUMO orbitals. This orbital overlap criterion may help to define the difference between “push-pull” systems in which electronic effects are mediated by the bridging moiety, and simpler systems in which the bridge acts as an electronically innocent spacer unit and through-space charge transfer/separation is dominant.

scholarly journals On differential operators and unifying relations for 1-loop Feynman integrands

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Kang Zhou
Keyword(s):  
Sigma Model ◽  
Differential Operators ◽  
Linear Sigma Model ◽  
Tree Level ◽  
Maxwell Theory ◽  
Scalar Theory ◽  
Yang Mills ◽  
Loop Level ◽  
Wide Range ◽  
Non Linear

Abstract We generalize the unifying relations for tree amplitudes to the 1-loop Feynman integrands. By employing the 1-loop CHY formula, we construct differential operators which transmute the 1-loop gravitational Feynman integrand to Feynman integrands for a wide range of theories, including Einstein-Yang-Mills theory, Einstein-Maxwell theory, pure Yang-Mills theory, Yang-Mills-scalar theory, Born-Infeld theory, Dirac-Born-Infeld theory, bi-adjoint scalar theory, non-linear sigma model, as well as special Galileon theory. The unified web at 1-loop level is established. Under the well known unitarity cut, the 1-loop level operators will factorize into two tree level operators. Such factorization is also discussed.

scholarly journals Fermion mass hierarchies from supersymmetric gauged flavour symmetry in 5D

2021 ◽  
Vol 10 (6) ◽  
Author(s):  
Ketan Patel
Keyword(s):  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Fermion Mass ◽  
Order Unity ◽  
Anomaly Cancellation ◽  
Fundamental Parameters ◽  
Yukawa Couplings ◽  
Fifth Dimension ◽  
Fermion Masses ◽  
The Masses

A mechanism to generate realistic fermion mass hierarchies based on supersymmetric gauged U(1)_FU(1)F symmetry in flat five-dimensional (5D) spacetime is proposed. The fifth dimension is compactified on S^1/Z_2S1/Z2 orbifold. The standard model fermions charged under the extra abelian symmetry along with their superpartners live in the 5D bulk. Bulk masses of fermions are generated by the vacuum expectation value of N=2N=2 superpartner of U(1)_FU(1)F gauge field, and they are proportional to U(1)_FU(1)F charges of respective fermions. This decides localization of fermions in the extra dimension, which in turn gives rise to exponentially suppressed Yukawa couplings in the effective 4D theory. Anomaly cancellation puts stringent constraints on the allowed U(1)_FU(1)F charges which leads to correlations between the masses of quarks and leptons. We perform an extensive numerical scan and obtain several solutions for anomaly-free U(1)_FU(1)F, which describe the observed pattern of fermion masses and mixing with all the fundamental parameters of order unity. It is found that the possible existence of SM singlet neutrinos substantially improves the spectrum of solutions by offering more freedom in choosing U(1)_FU(1)F charges. The model predicts Z^\primeZ′ boson mediating flavour violating interactions in both the quark and lepton sectors with the couplings which can be explicitly determined from the Yukawa couplings.

The Electrostatic Moments of a Charge Distribution

1997 ◽  
Author(s):  
Philip Coppens
Keyword(s):  
Dipole Moment ◽  
Charge Distribution ◽  
Dipole Moments ◽  
Practical Importance ◽  
Diffraction Method ◽  
Quadrupole Moments ◽  
Charge Densities ◽  
Moment Vector ◽  
Experimental Values ◽  
A Charge

The moments of a charge distribution provide a concise summary of the nature of that distribution. They are suitable for quantitative comparison of experimental charge densities with theoretical results. As many of the moments can be obtained by spectroscopic and dielectric methods, the comparison between techniques can serve as a calibration of experimental and theoretical charge densities. Conversely, since the full charge density is not accessible by the other experimental methods, the comparison provides an interpretation of the results of the complementary physical techniques. The electrostatic moments are of practical importance, as they occur in the expressions for intermolecular interactions and the lattice energies of crystals. The first electrostatic moment from X-rays was obtained by Stewart (1970), who calculated the dipole moment of uracil from the least-squares valence-shell populations of each of the constituent atoms of the molecule. Stewart’s value of 4.0 ± 1.3 D had a large experimental uncertainty, but is nevertheless close to the later result of 4.16 ± 0.4 D (Kulakowska et al. 1974), obtained from capacitance measurements of a solution in dioxane. The diffraction method has the advantage that it gives not only the magnitude but also the direction of the dipole moment. Gas-phase microwave measurements are also capable of providing all three components of the dipole moment, but only the magnitude is obtained from dielectric solution measurements. We will use an example as illustration. The dipole moment vector for formamide has been determined both by diffraction and microwave spectroscopy. As the diffraction experiment measures a continuous charge distribution, the moments derived are defined in terms of the method used for space partitioning, and are not necessarily equal. Nevertheless, the results from different techniques agree quite well. A comprehensive review on molecular electric moments from X-ray diffraction data has been published by Spackman (1992). Spackman points out that despite a large number of determinations of molecular dipole moments and a few determinations of molecular quadrupole moments, it is not yet widely accepted that diffraction methods lead to valid experimental values of the electrostatic moments.

scholarly journals Charged scalar production at the compact linear collider for the $$S_3 \otimes \mathbb {Z}_2$$ model

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
G. De Conto ◽  
A. C. B. Machado ◽  
J. Montaño ◽  
P. Chimenti
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Linear Collider ◽  
Direct Detection ◽  
Indirect Detection ◽  
Tree Level ◽  
Charged Scalar ◽  
Exotic Particles ◽  
Small Influence ◽  
The Masses

AbstractWe present a model with $$S_3 \otimes \mathbb {Z}_2$$ S 3 ⊗ Z 2 model plus a sterile neutrino and its phenomenological expectations for the production of charged scalars at the compact linear collider. At tree level, our model predicts a total cross section in between 0.1 and $$10^{-5}$$ 10 - 5 pb for the $$e^- e^+ \rightarrow H^+ H^-$$ e - e + → H + H - process, considering all possible mass values for the charged scalar in the CLIC experiment. We also show that this prediction holds regardless of the masses of the other exotic particles and their couplings. We also show that an indirect detection from its effects in the $$e \overline{e} \rightarrow e \overline{e}$$ e e ¯ → e e ¯ + missing energy process is possible under specific conditions, or a direct detection under other circumstances. However, one cannot use this process to study the sterile neutrinos present in this model, given that they have a small influence in the total cross-section for the direct detection of the exotic scalar to be possible.

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