scholarly journals Exploring multi-Higgs models with softly broken large discrete symmetry groups

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
Ivo de Medeiros Varzielas ◽  
Igor P. Ivanov ◽  
Miguel Levy
Keyword(s):  
General Procedure ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Discrete Symmetry ◽  
Higgs Doublet ◽  
Structural Features ◽  
Symmetry Groups ◽  
Symmetric Model ◽  
Exact Symmetry ◽  
Symmetric Vacuum

AbstractWe develop methods to study the scalar sector of multi-Higgs models with large discrete symmetry groups that are softly broken. While in the exact symmetry limit, the model has very few parameters and can be studied analytically, proliferation of quadratic couplings in the most general softly broken case makes the analysis cumbersome. We identify two sets of soft breaking terms which play different roles: those which preserve the symmetric vacuum expectation value alignment, and the remaining terms which shift it. Focusing on alignment preserving terms, we check which structural features of the symmetric parent model are conserved and which are modified. We find remarkable examples of structural features which are inherited from the parent symmetric model and which persist even when no exact symmetry is left. The general procedure is illustrated with the example of the three-Higgs-doublet model with the softly broken symmetry group $$\Sigma (36)$$ Σ ( 36 ) .

scholarly journals Minimal scoto-seesaw mechanism with spontaneous CP violation

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
D. M. Barreiros ◽  
F. R. Joaquim ◽  
R. Srivastava ◽  
J. W. F. Valle
Keyword(s):  
Dark Matter ◽  
Cp Violation ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Discrete Symmetry ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Seesaw Mechanism ◽  
Cosmological Observations ◽  
Scalar Singlet

Abstract We propose simple scoto-seesaw models to account for dark matter and neutrino masses with spontaneous CP violation. This is achieved with a single horizontal $$ {\mathcal{Z}}_8 $$ Z 8 discrete symmetry, broken to a residual $$ {\mathcal{Z}}_2 $$ Z 2 subgroup responsible for stabilizing dark matter. CP is broken spontaneously via the complex vacuum expectation value of a scalar singlet, inducing leptonic CP-violating effects. We find that the imposed $$ {\mathcal{Z}}_8 $$ Z 8 symmetry pushes the values of the Dirac CP phase and the lightest neutrino mass to ranges already probed by ongoing experiments, so that normal-ordered neutrino masses can be cornered by cosmological observations and neutrinoless double beta decay experiments.

SPONTANEOUS CP VIOLATION IN A TWO-GENERATION LEFT-RIGHT SYMMETRIC MODEL WITH TWO HIGGS BI-DOUBLETS

1992 ◽  
Vol 07 (34) ◽  
pp. 3179-3186 ◽  
Author(s):  
AMBAR GHOSAL ◽  
ASIM K. RAY ◽  
SASWATI SARKAR
Keyword(s):  
Cp Violation ◽  
Relative Phase ◽  
Vacuum Expectation ◽  
Discrete Symmetry ◽  
Tree Level ◽  
Model Parameters ◽  
Symmetric Model ◽  
Expectation Values ◽  
Flavor Changing ◽  
Experimental Values

We discuss a two-generation left-right symmetric model with two Higgs bi-doublets and a discrete symmetry to show that spontaneous CP violation arises as a result of soft breaking of the discrete symmetry. The contributions to the CP violation parameter ε in the [Formula: see text] transition come from the box diagrams due to WL-WR exchanges as well as from the mixing of the real and imaginary parts of the flavor changing neutral Higgs at the tree level and both contributions depend on the relative phase difference between the vacuum expectation values (vevs) of the relevant neutral Higgs scalars. Other CP violating effects in the model are consistent with their experimental values for the appropriate choice of the model parameters. The extension of the model to the realistic case of three generations of fermions does not appreciably change the phenomenology of the model.

scholarly journals K0-K¯0 Mixing in the Minimal Flavor-Violating Two-Higgs-Doublet Models

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Natthawin Cho ◽  
Xin-Qiang Li ◽  
Fang Su ◽  
Xin Zhang
Keyword(s):  
Mass Difference ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Higgs Doublet ◽  
New Physics ◽  
Point Of View ◽  
Minimal Flavor Violation ◽  
Yukawa Couplings ◽  
Charged Higgs ◽  
Current Experimental Data

The two-Higgs-doublet model (2HDM), as one of the simplest extensions of the Standard Model (SM), is obtained by adding another scalar doublet to the SM and is featured by a pair of charged Higgs, which could affect many low-energy processes. In the “Higgs basis” for a generic 2HDM, only one scalar doublet gets a nonzero vacuum expectation value and, under the criterion of minimal flavor violation, the other one is fixed to be either color-singlet or color-octet, which are named as type III and type C 2HDM, respectively. In this paper, we study the charged-Higgs effects of these two models on the K0-K¯0 mixing, an ideal process to probe New Physics (NP) beyond the SM. Firstly, we perform a complete one-loop computation of the box diagrams relevant to the K0-K¯0 mixing, keeping the mass and momentum of the external strange quark up to the second order. Together with the up-to-date theoretical inputs, we then give a detailed phenomenological analysis, in the cases of both real and complex Yukawa couplings of the charged Higgs to quarks. The parameter spaces allowed by the current experimental data on the mass difference ΔmK and the CP-violating parameter ϵK are obtained and the differences between these two 2HDMs are investigated, which are helpful to distinguish them from each other from a phenomenological point of view.

SUPERSYMMETRIC LEFT–RIGHT MODELS WITH B-L ODD HIGGS DOUBLETS

2011 ◽  
Vol 26 (07n08) ◽  
pp. 1305-1326 ◽  
Author(s):  
DEBASISH BORAH
Keyword(s):  
Symmetry Breaking ◽  
Parity Violation ◽  
Gauge Coupling ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Higgs Doublet ◽  
Single Step ◽  
Seesaw Mechanism ◽  
The Cost ◽  
Exciting Possibility

We study various possible Supersymmetric Left–Right (SUSYLR) models with Higgs doublets carrying B-L charge ±1: with single step symmetry breaking down to the Minimal Supersymmetric Standard Model (MSSM) as well as multistep symmetry breaking. Single step symmetry breaking can be achieved with the minimal field content of just Higgs doublet and bidoublets whereas multistep symmetry breaking can be realized only at the cost of including additional Higgs superfields. However, going beyond the minimal field content comes up with the exciting possibility of TeV scale intermediate symmetry which can have important implications in the ongoing collider experiments. We show that spontaneous parity violation can be achieved naturally in all these models and R-parity is spontaneously broken by the vacuum expectation value of B-L odd Higgs doublets. The tiny neutrino mass can arise from a double seesaw mechanism in the presence of additional singlet or triplet fermions. We show that gauge coupling unification can be achieved in these models with the possibility of TeV scale intermediate symmetry in some specific nonminimal versions.

scholarly journals Left–right model from gauge-Higgs unification with dark matter

2015 ◽  
Vol 30 (12) ◽  
pp. 1550063 ◽  
Author(s):  
Francisco J. de Anda
Keyword(s):  
Dark Matter ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Dark Matter Candidate ◽  
Symmetric Model ◽  
Dimensional Model ◽  
Expectation Value ◽  
Fermion Masses ◽  
The Standard Model ◽  
Five Dimensional Model

We propose a five-dimensional model based on the idea of Gauge-Higgs Unification (GHU) with the gauge group SO(5) × U(1) in Randall–Sundrum (RS) spacetime. We obtain a left–right (LR) symmetric model with a stable scalar identified as a dark matter candidate. This stable scalar obtains a vacuum expectation value (VEV) that gives mass to fermions in the bulk through the Hosotani Mechanism. There is a scalar localized on a brane and gives contributions to fermion masses. This scalar fits the observed Higgs boson data. We are able to fit all the Standard Model (SM) observables while evading constraints.

scholarly journals Invisible KL decays in the SM extensions

2016 ◽  
Vol 31 (25) ◽  
pp. 1650142 ◽  
Author(s):  
S. N. Gninenko ◽  
N. V. Krasnikov
Keyword(s):  
Standard Model ◽  
Branching Ratio ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Higgs Doublet ◽  
New Physics ◽  
Doublet Model ◽  
Strong Motivation ◽  
Two Higgs Doublet Model ◽  
Near Future

In the Standard Model (SM), the branching ratio for the decay [Formula: see text] is helicity suppressed and predicted to be very small [Formula: see text]. We consider two natural extensions of the SM as the two-Higgs-doublet model (2HDM) and the neutrino minimal Standard Model ([Formula: see text]MSM) with additional singlet scalar, whose main feature is that they can lead to an enhanced [Formula: see text]. In the 2HDM, the smallness of the neutrino mass is explained due to the smallness of the second Higgs doublet vacuum expectation value. Moreover, the [Formula: see text]MSM extension with additional singlet field can explain the [Formula: see text] anomaly. The considered models demonstrate that the [Formula: see text] decay is a clean probe of new physics scale well above 100 TeV, that is complementary to rare [Formula: see text] decay, and provide a strong motivation for its sensitive search in a near future low-energy experiment.

Dark energy from nondegenerate Higgs-vacuum

2019 ◽  
Vol 28 (16) ◽  
pp. 2040008
Author(s):  
Muhammad Usman ◽  
Asghar Qadir
Keyword(s):  
Dark Energy ◽  
Higgs Field ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Scalar Fields ◽  
Higgs Doublet ◽  
Late Time ◽  
True Vacuum ◽  
Doublet Model ◽  
Two Higgs Doublet Model

Scalar fields are favorite among the possible candidates for the dark energy. Most frequently discussed are those with degenerate minima at [Formula: see text]. In this paper, a slightly modified two-Higgs doublet model is taken to contain the Higgs field(s) as the dark energy candidate(s). The model considered has two nondegenerate minima at [Formula: see text], instead of one degenerate minimum at [Formula: see text]. The component fields of one SU(2) doublet ([Formula: see text]) act as the standard model (SM) Higgs, while the component fields of the second doublet ([Formula: see text]) are taken to be the dark energy candidates (lying in the true vacuum). It is found that one can arrange for late time acceleration (dark energy) by using an SU(2) Higgs doublet, whose vacuum expectation value is zero, in the quintessential regime.

FERMION SPECTRA AND KM MATRICES IN A LEFT-RIGHT SYMMETRIC MODEL FROM CALABI-YAU STRING COMPACTIFICATION

1993 ◽  
Vol 08 (29) ◽  
pp. 5235-5263
Author(s):  
CHUICHIRO HATTORI ◽  
MASAHISA MATSUDA ◽  
TAKEO MATSUOKA ◽  
DAIZO MOCHINAGA
Keyword(s):  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Current Data ◽  
Fourth Generation ◽  
Spontaneous Breaking ◽  
Neutrino Masses ◽  
Symmetric Model ◽  
Seesaw Mechanism ◽  
Flavor Changing ◽  
O 10

We study a left-right symmetric type of the effective low-energy theory induced from the four-generation superstring model. The spontaneous breaking of the R-parity occurs through a nonzero vacuum expectation value (VEV) of the fourth generation right-handed sneutrino (νR). It is predicted that the lightest chargino is lighter than 113 GeV. By virtue of the seesaw mechanism we can explain the smallness of neutrino masses for three generations and the largeness of the fourth generation neutrino mass. The mixing in the color-singlet sector yields nontrivial KM matrices which bring about flavor-changing interactions. If we take νR=O(10 TeV ), our results are consistent with the current data except for the solar neutrino problem.

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