scholarly journals Investigation of the scalar spectrum in SU (3) with eight degenerate flavors

2017 ◽  
Vol 32 (35) ◽  
pp. 1747002 ◽  
Author(s):  
E. Rinaldi
Keyword(s):  
Axial Vector ◽  
Mass Range ◽  
Fermion Mass ◽  
Axial Vector Meson ◽  
Vector Resonance ◽  
Quantum Numbers ◽  
Fermion Masses ◽  
The One ◽  
The Masses ◽  
Fermion Action

The Lattice Strong Dynamics collaboration is investigating the properties of a SU(3) gauge theory with [Formula: see text] light fermions on the lattice. We measure the masses of the lightest pseudoscalar, scalar and vector states using simulations with the nHYP staggered-fermion action on large volumes and at small fermion masses, reaching [Formula: see text]. The axial-vector meson and the nucleon are also studied for the same range of fermion masses. One of the interesting features of this theory is the dynamical presence of a light flavor-singlet scalar state with [Formula: see text] quantum numbers that is lighter than the vector resonance and has a mass consistent with the one of the pseudoscalar state for the whole fermion mass range explored. We comment on the existence of such state emerging from our lattice simulations and on the challenges of its analysis. Moreover we highlight the difficulties in pursuing simulations in the chiral regime of this theory using large volumes.

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.

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.

scholarly journals Fermion mass hierarchy in grand gauge-Higgs unification

2019 ◽  
Vol 2019 (8) ◽  
Author(s):  
Nobuhito Maru ◽  
Yoshiki Yatagai
Keyword(s):  
Top Quark ◽  
Electroweak Symmetry Breaking ◽  
Boson Mass ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Electroweak Symmetry ◽  
Fermion Masses ◽  
The Standard Model ◽  
Mass Terms ◽  
The One

Abstract Grand gauge-Higgs unification of 5D $SU(6)$ gauge theory on an orbifold $S^1/Z_2$ is discussed. The Standard Model (SM) fermions are introduced on one of the boundaries and some massive bulk fields are also introduced so that they couple to the SM fermions through the mass terms on the boundary. Integrating out the bulk fields generates SM fermion masses with exponentially small bulk mass dependences. The SM fermion masses except for the top quark are shown to be reproduced by mild tuning of the bulk masses. The one-loop Higgs potential is calculated and it is shown that electroweak symmetry breaking occurs by introducing additional bulk fields. The Higgs boson mass is also computed.

scholarly journals THEORY OF ELECTROWEAK INTERACTIONS WITHOUT SPONTANEOUS SYMMETRY BREAKING

2001 ◽  
Vol 16 (25) ◽  
pp. 4171-4188 ◽  
Author(s):  
BING AN LI
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Z Boson ◽  
W Boson ◽  
Axial Vector ◽  
Fermion Mass ◽  
Electroweak Theory ◽  
Intermediate Boson ◽  
Generating Functional ◽  
Fermion Masses

An electroweak theory without spontaneous symmetry breaking is studied in this paper. A new symmetry breaking of SU (2)L × U (1), axial-vector symmetry breaking, caused by the combination of the axial-vector component of the intermediate boson and the fermion mass is found in electroweak theory. The mass of the W boson is resulted in the combination of the axial-vector symmetry breaking and the explicit symmetry breaking by the fermion masses. The Z boson gains mass from the axial-vector symmetry breaking only. [Formula: see text], [Formula: see text], and [Formula: see text] are obtained. They are in excellent agreement with data. The SU (2)L × U (1) invariant generating functional of the Green functions is constructed and the theory is proved to be renormalizable.

Masses of W and Z bosons without spontaneous symmetry breaking

2001 ◽  
Vol 16 (supp01a) ◽  
pp. 351-353
Author(s):  
Bing An Li
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Axial Vector ◽  
Z Bosons ◽  
Dynamical Symmetry ◽  
Fermion Mass ◽  
Electroweak Theory ◽  
Dynamical Symmetry Breaking ◽  
Vector Component ◽  
The Masses

A new dynamical symmetry breaking of SU(2)L × U(1) caused by the combination of the axial-vector component and the fermion mass is found in electroweak theory. The masses of the W and the Z bosons are obtained to be [Formula: see text] and [Formula: see text]. The Fermi constant is determined to be [Formula: see text].

scholarly journals DYNAMICAL FERMION MASSES UNDER THE INFLUENCE OF KALUZA–KLEIN FERMIONS AND A BULK ABELIAN GAUGE FIELD

2010 ◽  
Vol 25 (35) ◽  
pp. 2933-2945 ◽  
Author(s):  
D. EBERT ◽  
V. CH. ZHUKOVSKY ◽  
A. V. TYUKOV
Keyword(s):  
Gauge Field ◽  
Effective Potential ◽  
Dynamical Variable ◽  
Fermion Mass ◽  
Coupling Constant ◽  
Mass Generation ◽  
Abelian Gauge ◽  
Fifth Dimension ◽  
Fermion Masses ◽  
The Masses

The dynamical fermion mass generation on the 3-brane in the 5D spacetime is discussed in a model with bulk fermions in interaction with fermions on the branes assuming the presence of a constant Abelian gauge field A5 in the bulk. We calculate the effective potential as a function of the fermion masses and the gauge field A5. The masses can be found from the stationarity condition for the effective potential (the gap equation). We formulate the equation for the mass spectrum of the 4D-fermions. The phases with finite and vanishing fermion masses are studied and the dependence of the masses on the radius of the fifth dimension is analyzed. The influence of the A5-gauge field on the symmetry breaking is considered both when this field is a background parameter and a dynamical variable. The critical values of the A5 field, the coupling constant and the radius are examined.

scholarly journals DYNAMICAL FERMION MASSES UNDER THE INFLUENCE OF KALUZA–KLEIN FERMIONS IN EXTRA DIMENSIONS

2000 ◽  
Vol 15 (06) ◽  
pp. 445-454 ◽  
Author(s):  
HIROYUKI ABE ◽  
HIRONORI MIGUCHI ◽  
TAIZO MUTA
Keyword(s):  
Extra Dimensions ◽  
Critical Radius ◽  
Dimensional Space ◽  
Fermion Mass ◽  
Mass Generation ◽  
Fermion Masses ◽  
The Masses ◽  
Kaluza Klein

The dynamical fermion mass generation in the four-dimensional brane is discussed in a model with five-dimensional Kaluza–Klein fermions in interaction with four-dimensional fermions. It is found that the dynamical fermion masses are generated beyond the critical radius of the compactified extra dimensional space and may be made small compared with the masses of the Kaluza–Klein modes.

scholarly journals SU(3) sextet model with Wilson fermions

2018 ◽  
Vol 175 ◽  
pp. 08018
Author(s):  
Martin Hansen ◽  
Claudio Pica
Keyword(s):  
Quark Mass ◽  
Weak Coupling ◽  
Chiral Limit ◽  
Axial Vector ◽  
Qualitative Behavior ◽  
Infinite Volume ◽  
Axial Vector Meson ◽  
Coupling Phase ◽  
Decay Constants ◽  
The Masses

We present our final results for the SU(3) sextet model with the non-improved Wilson fermion discretization. We find evidence for several phases of the lattice model, including a bulk phase with broken chiral symmetry. We study the transition between the bulk and weak coupling phase which corresponds to a significant change in the qualitative behavior of spectral and scale setting observables. In particular the t0 and w0 observables seem to diverge in the chiral limit in the weak coupling phase. We then focus on the study of spectral observables in the chiral limit in the weak coupling phase at infinite volume. We consider the masses and decay constants for the pseudoscalar and vector mesons, the mass of the axial vector meson and the spin-1/2 baryon as a function of the quark mass, while controlling finite volume effects. We then test our data against both the IR conformal and the chirally broken hypotheses. Preprint: CP3-Origins-2017-49 DNRF90

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.

GAUGE BOSON MASSES FROM FERMION MASSES?

1992 ◽  
Vol 07 (22) ◽  
pp. 1991-1996 ◽  
Author(s):  
R. FOOT ◽  
S. TITARD
Keyword(s):  
Gauge Boson ◽  
Z Boson ◽  
Heavy Fermions ◽  
Mass Matrix ◽  
Gauge Bosons ◽  
Fermion Masses ◽  
The Masses

We examine the possibility that the masses of the W and Z gauge bosons are induced radiatively from the masses of heavy fermions. From experiment we know that [Formula: see text][Formula: see text]. We point out that this relation can be naturally obtained if the W and Z boson masses are radiatively generated from heavy fermions which arise from a mass matrix which has large electroweak violating masses as well as very large electroweak invariant masses. Two examples of this are considered: The usual see-saw neutrino model and the SU(5)c/quark-lepton symmetric models.

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