scholarly journals CHARGED RIGHT-HANDED CURRENTS IN THE LEPTOQUARK–BILEPTON FLAVOR DYNAMICS

1999 ◽  
Vol 14 (32) ◽  
pp. 2223-2228 ◽  
Author(s):  
A. A. MACHADO ◽  
F. PISANO
Keyword(s):  
Standard Model ◽  
Gauge Theories ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Gauge Bosons

Flavor dynamics chiral models of leptoquark fermions and bilepton gauge bosons with masses up to a few TeV, although coincident with physics of the Fermi scale standard model, address the fermion mass hierarchy and explain the flavor question. The presence of charged right-handed weak currents coupled to bileptons, which we point out here, is another feature of these chiral semisimple gauge theories.

scholarly journals THE DUALIZED STANDARD MODEL AND ITS APPLICATIONS — AN INTERIM REPORT

1999 ◽  
Vol 14 (14) ◽  
pp. 2173-2203 ◽  
Author(s):  
HONG-MO CHAN ◽  
SHEUNG TSUN TSOU
Keyword(s):  
Standard Model ◽  
High Energy ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Matrix Elements ◽  
Ckm Matrix ◽  
High Energy Cosmic Rays ◽  
Perturbative Method ◽  
Ckm Matrix Elements ◽  
Physical Consequences

Based on a non-Abelian generalization of electric–magnetic duality, the Dualized Standard Model (DSM) suggests a natural explanation for exactly three generations of fermions as the "dual colour" [Formula: see text] symmetry broken in a particular manner. The resulting scheme then offers on the one hand a fermion mass hierarchy and a perturbative method for calculating the mass and mixing parameters of the Standard Model fermions, and on the other hand testable predictions for new phenomena ranging from rare meson decays to ultra-high energy cosmic rays. Calculations to one-loop order gives, at the cost of adjusting only three real parameters, values for the following quantities all (except one) in very good agreement with experiment: the quark CKM matrix elements ‖Vrs‖, the lepton CKM matrix elements ‖Urs‖, and the second generation masses mc, ms, mμ. This means, in particular, that it gives near maximal mixing Uμ3 between νμ and ντ as observed by SuperKamiokande, Kamiokande and Soudan, while keeping small the corresponding quark angles Vcb, Vts. In addition, the scheme gives (i) rough order-of-magnitude estimates for the masses of the lowest generation, (ii) predictions for low energy FCNC effects such as KL→ eμ, and (iii) a possible explanation for the long-standing puzzle of air showers beyond the GZK cut-off. All these together, however, still represent but a portion of the possible physical consequences derivable from the DSM scheme, the majority of which are yet to be explored.

scholarly journals A bottom-up approach to fermion mass hierarchy: a case with vector-like fermions

2020 ◽  
Vol 2020 (4) ◽  
Author(s):  
Yoshiharu Kawamura
Keyword(s):  
Standard Model ◽  
Yukawa Coupling ◽  
High Energy ◽  
Fine Tuning ◽  
Fermion Mass ◽  
Extended Model ◽  
Mass Hierarchy ◽  
Bottom Up ◽  
Existence Proofs ◽  
The Standard Model

Abstract We propose a bottom-up approach in which a structure of high-energy physics is explored by accumulating existence proofs and/or no-go theorems in the standard model or its extension. As an illustration, we study fermion mass hierarchies based on an extension of the standard model with vector-like fermions. It is shown that the magnitude of elements of Yukawa coupling matrices can become $O(1)$ and a Yukawa coupling unification can be realized in a theory beyond the extended model, if vector-like fermions mix with three families. In this case, small Yukawa couplings in the standard model can be highly sensitive to a small variation of matrix elements, and it seems that the mass hierarchy occurs as a result of fine tuning.

scholarly journals The Clockwork Standard Model

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Yoo-Jin Kang ◽  
Soonbin Kim ◽  
Hyun Min Lee
Keyword(s):  
Standard Model ◽  
Mass Parameter ◽  
Planck Scale ◽  
Fine Tuning ◽  
Mass Hierarchy ◽  
Gauge Bosons ◽  
Five Dimensions ◽  
Expansion Parameter ◽  
Bulk Mass ◽  
Linear Dilaton

Abstract We consider various bulk fields with general dilaton couplings in the linear dilaton background in five dimensions as the continuum limit of clockwork models. We show that the localization of the zero modes of bulk fields and the mass gap in the KK spectrum depend not only on the bulk dilaton coupling, but also on the bulk mass parameter in the case of a bulk fermion. The consistency from universality and perturbativity of gauge couplings constrain the dilaton couplings to the brane-localized matter fields as well as the bulk gauge bosons. Constructing the Clockwork Standard Model (SM) in the linear dilaton background, we provide the necessary conditions for the bulk mass parameters for explaining the mass hierarchy and mixing for the SM fermions. We can introduce a sizable expansion parameter ε = $$ {e}^{-\frac{2}{3}{kz}_c} $$ e − 2 3 kz c for the realistic flavor structure in the quark sector without a fine-tuning in the bulk mass parameters, but at the expense of a large 5D Planck scale. On the other hand, we can use a smaller expansion parameter for lepton masses, in favor of the solution to the hierarchy problem of the Higgs mass parameter. We found that massive Kaluza-Klein (KK) gauge bosons and massive KK gravitons couple more strongly to light and heavy fermions, respectively, so there is a complementarity in the resonance researches for those KK modes at the LHC.

scholarly journals A road towards a beyond the Standard Model model

2022 ◽  
Vol 258 ◽  
pp. 06003
Author(s):  
Giancarlo Rossi
Keyword(s):  
Standard Model ◽  
Chiral Symmetry ◽  
Top Quark ◽  
Gauge Coupling ◽  
Spontaneous Breaking ◽  
Strong Interactions ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Strongly Interacting ◽  
Fermion Masses

In this talk we describe examples of renormalizable strongly interacting field theories where chiral symmetry, broken at the UV cutoff by the presence of some irrelevant d > 4 operators in the fundamental Lagrangian, is recovered at low energy owing to the tuning of certain Lagrangian parameters. The interference of UV effects with IR features coming from the spontaneous breaking of the recovered chiral symmetry yields non perturbatively generated elementary fermion masses parametrically expressed by formulae of the kind mq ~ Cq(α)ΛRGI with α the gauge coupling constant and ΛRGI the RGI scale of the theory. Upon introducing EW interactions, this mechanism can be extended to give mass to EW bosons and leptons and can thus be used as an alternative to the Higgs scenario. In order to give the top quark and the weak gauge bosons a mass of the phenomenologically correct order of magnitude, the model must necessarily include (yet unobserved) super-strongly interacting massive fermions endowed, besides ordinary Standard Model interactions, with super-strong interactions with a RGI scale, ΛT ΛQCD in the few TeV range. Though limited in its scope (here we ignore hypercharge and leptons and discuss only the case of one family neglecting weak isospin splitting), the model opens the way to a solution of the naturalness problem and an understanding of the fermion mass hierarchy.

scholarly journals Flavoured warped axion

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Quentin Bonnefoy ◽  
Peter Cox ◽  
Emilian Dudas ◽  
Tony Gherghetta ◽  
Minh D. Nguyen
Keyword(s):  
Scalar Field ◽  
Standard Model ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Complex Scalar ◽  
Fermion Masses ◽  
Complex Scalar Field ◽  
Hierarchy Problems

Abstract We consider a 5D extension of the DFSZ axion model that addresses both the axion quality and fermion mass hierarchy problems, and predicts flavour-dependent, off-diagonal axion-fermion couplings. The axion is part of a 5D complex scalar field charged under a U(1)PQ symmetry that is spontaneously broken in the bulk, and is insensitive to explicit PQ breaking on the UV boundary. Bulk Standard Model fermions interact with two Higgs doublets that can be localized on the UV boundary or propagate in the bulk to explain the fermion masses and mixings. When the Higgs doublets are localized on the UV boundary, they induce flavour diagonal couplings between the fermions and the axion. However, when the Higgs doublets propagate in the bulk, the overlap of the axion and fermion profiles generates flavour off-diagonal couplings. The effective scale of these off-diagonal couplings in both the quark and lepton sectors can be as small as 1011 GeV, and therefore will be probed in future precision flavour experiments.

scholarly journals Comment on Z′'s and the H1 and ZEUS High Q2 Anomalies

1997 ◽  
Vol 12 (25) ◽  
pp. 1859-1863 ◽  
Author(s):  
Stephen Godfrey
Keyword(s):  
Standard Model ◽  
Cross Section ◽  
Gauge Theories ◽  
Statistical Evidence ◽  
Contact Interactions ◽  
Gauge Bosons ◽  
High Q ◽  
The Standard Model ◽  
Existing Data ◽  
Scaling Arguments

We investigate the effects of extra neutral gauge bosons on the high Q2 region of the e+p→ e+X cross-section at [Formula: see text] GeV. We found that the only models with electroweak strength coupling, typical of extended gauge theories, that give a better fit to the H1 and ZEUS high Q2 data than the standard model, are ruled out by the existing data from the Tevatron. From general scaling arguments, using the allowed contact interactions, the only allowed models with Z′'s would be those with strong couplings although even in this case the statistical evidence is not compelling.

scholarly journals A unified Yukawa interaction for the Standard Model of quarks and leptons

2021 ◽  
Vol 36 (27) ◽  
pp. 2150196
Author(s):  
Ying Zhang
Keyword(s):  
Standard Model ◽  
Mass Matrix ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Yukawa Interaction ◽  
Flavor Structure ◽  
Fermion Masses ◽  
The Standard Model ◽  
Matrix Formula

To address fermion mass hierarchy and flavor mixings in the quark and lepton sectors, a minimal flavor structure without any redundant parameters beyond phenomenological observables is proposed via decomposition of the Standard Model Yukawa mass matrix into a bi-unitary form. After reviewing the roles and parameterization of the factorized matrix [Formula: see text] and [Formula: see text] in fermion masses and mixings, we generalize the mechanism to up- and down-type fermions to unify them into a universal quark/lepton Yukawa interaction. In the same way, a unified form of the description of the quark and lepton Yukawa interactions is also proposed, which shows a similar picture as the unification of gauge interactions.

scholarly journals A first test of the framed standard model against experiment

2015 ◽  
Vol 30 (11) ◽  
pp. 1550051 ◽  
Author(s):  
José Bordes ◽  
Hong-Mo Chan ◽  
Sheung Tsun Tsou
Keyword(s):  
Standard Model ◽  
Mass Matrix ◽  
Internal Symmetry ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Order Unity ◽  
Changing Scale ◽  
The Standard Model ◽  
Symmetry Space ◽  
Fermion Mass Matrix

The framed standard model (FSM) is obtained from the standard model by incorporating, as field variables, the frame vectors (vielbeins) in internal symmetry space. It gives the standard Higgs boson and 3 generations of quarks and leptons as immediate consequences. It gives moreover a fermion mass matrix of the form: m = mTαα†, where α is a vector in generation space independent of the fermion species and rotating with changing scale, which has already been shown to lead, generically, to up–down mixing, neutrino oscillations and mass hierarchy. In this paper, pushing the FSM further, one first derives to 1-loop order the RGE for the rotation of α, and then applies it to fit mass and mixing data as a first test of the model. With 7 real adjustable parameters, 18 measured quantities are fitted, most (12) to within experimental error or to better than 0.5 percent, and the rest (6) not far off. (A summary of this fit can be found in Table 2 of this paper.) Two notable features, both generic to FSM, not just specific to the fit, are: (i) that a theta-angle of order unity in the instanton term in QCD would translate via rotation into a Kobayashi–Maskawa phase in the CKM matrix of about the observed magnitude (J ~ 10-5), (ii) that it would come out correctly that mu < md, despite the fact that mt ≫ mb, mc ≫ ms. Of the 18 quantities fitted, 12 are deemed independent in the usual formulation of the standard model. In fact, the fit gives a total of 17 independent parameters of the standard model, but 5 of these have not been measured by experiment.

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