scholarly journals Fitting the $$ Zb\overline{b} $$ vertex in the two-Higgs-doublet model and in the three-Higgs-doublet model

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Darius Jurčiukonis ◽  
Luís Lavoura
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Opposite Sign ◽  
Higgs Doublet ◽  
Yukawa Couplings ◽  
The Standard Model ◽  
Doublet Model ◽  
The One ◽  
Two Higgs Doublet Model

Abstract We investigate the new contributions to the parameters gL and gR of the $$ Zb\overline{b} $$ Zb b ¯ vertex in a multi-Higgs-doublet model (MHDM). We emphasize that those contributions generally worsen the fit of those parameters to the experimental data. We propose a solution to this problem, wherein gR has the opposite sign from the one predicted by the Standard Model; this solution, though, necessitates light scalars and large Yukawa couplings in the MHDM.

ONE LOOP-INDUCED WZH COUPLING IN THE TWO HIGGS DOUBLET MODEL

1989 ◽  
Vol 04 (28) ◽  
pp. 2757-2766 ◽  
Author(s):  
THOMAS G. RIZZO
Keyword(s):  
Standard Model ◽  
Higgs Doublet ◽  
New Physics ◽  
Tree Level ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Charged Higgs ◽  
Doublet Model ◽  
The One ◽  
Two Higgs Doublet Model

Although absent at the tree level in models with only doublet and singlet Higgs representations, the WZH coupling can be induced at the one-loop level. We examine the size of this induced coupling in the two Higgs doublet model due to fermion as well as Higgs/gauge boson loops. Such couplings could provide a new mechanism for charged Higgs production at colliders and are ‘backgrounds’ to new physics beyond the Standard Model. We find, however, that these couplings are very weak for all regions of the parameter space explored.

scholarly journals Two-loop matching of renormalizable operators: general considerations and applications

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Henning Bahl ◽  
Ivan Sobolev
Keyword(s):  
Standard Model ◽  
Higgs Doublet ◽  
High Energy ◽  
Effective Field ◽  
Matching Conditions ◽  
Loop Level ◽  
Doublet Model ◽  
The One ◽  
Diagrammatic Method ◽  
Two Higgs Doublet Model

Abstract Low-energy effective field theories (EFT) encode information about the physics at high energies — i.e., the high-energy theory (HET). To extract this information the EFT and the HET have to be matched to each other. At the one-loop level, general results for the matching of renormalizable operators have already been obtained in the literature. In the present paper, we take a step towards a better understanding of renormalizable operator matching at the two-loop level: focusing on the diagrammatic method, we discuss in detail the various contributions to two-loop matching conditions and compare different approaches to derive them. Moreover, we discuss which observables are best suited for the derivation of matching conditions. As a concrete application, we calculate the $$ \mathcal{O}\left({\alpha}_t{\alpha}_s\right) $$ O α t α s and $$ \mathcal{O}\left({\alpha}_t^2\right) $$ O α t 2 matching conditions of the scalar four-point couplings between the Standard Model (SM) and the Two-Higgs-Doublet Model (THDM) as well as the THDM and the Minimal Supersymmetric Standard Model (MSSM). We use the derived formulas to improve the prediction of the SM-like Higgs mass in the MSSM using the THDM as EFT.

scholarly journals Grand Unified Origin of Gauge Interactions and Families Replication in the Standard Model

Universe ◽  
2021 ◽  
Vol 7 (12) ◽  
pp. 461
Author(s):  
António P. Morais ◽  
Roman Pasechnik ◽  
Werner Porod
Keyword(s):  
Standard Model ◽  
Higgs Doublet ◽  
New Physics ◽  
Effective Field ◽  
Tree Level ◽  
Emergent Properties ◽  
Grand Unified Theory ◽  
Yukawa Couplings ◽  
The Standard Model ◽  
Doublet Model

The tremendous phenomenological success of the Standard Model (SM) suggests that its flavor structure and gauge interactions may not be arbitrary but should have a fundamental first-principle explanation. In this work, we explore how the basic distinctive properties of the SM dynamically emerge from a unified New Physics framework tying together both flavor physics and Grand Unified Theory (GUT) concepts. This framework is suggested by a novel anomaly-free supersymmetric chiral E6×SU(2)F×U(1)F GUT containing the SM. Among the most appealing emergent properties of this theory is the Higgs-matter unification with a highly-constrained massless chiral sector featuring two universal Yukawa couplings close to the GUT scale. At the electroweak scale, the minimal SM-like effective field theory limit of this GUT represents a specific flavored three-Higgs doublet model consistent with the observed large hierarchies in the quark mass spectra and mixing already at tree level.

scholarly journals The muon g – 2 for low-mass pseudoscalar Higgs in the general 2HDM

2018 ◽  
Vol 179 ◽  
pp. 01022
Author(s):  
Adriano Cherchiglia ◽  
Dominik Stöckinger ◽  
Hyejung Stöckinger-Kim
Keyword(s):  
Large Deviation ◽  
Higgs Doublet ◽  
Type Ii ◽  
Parameter Region ◽  
Yukawa Couplings ◽  
The Standard Model ◽  
Low Mass ◽  
Doublet Model ◽  
Two Higgs Doublet Model ◽  
Theory And Experiment

The two-Higgs doublet model is a simple and attractive extension of the Standard Model. It provides a possibility to explain the large deviation between theory and experiment in the muon g – 2 in an interesting parameter region: light pseudoscalar Higgs A, large Yukawa coupling to τ-leptons, and general, non-type II Yukawa couplings are preferred. This parameter region is explored, experimental limits on the relevant Yukawa couplings are obtained, and the maximum possible contributions to the muon g – 2 are discussed.

scholarly journals Direct CP violation in $$D^+ \rightarrow K^0({\bar{K}}^0) \pi ^+$$ decays as a probe for new physics

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
David Delepine ◽  
Gaber Faisel ◽  
Carlos A. Ramirez
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Parameter Space ◽  
Higgs Doublet ◽  
New Physics ◽  
Cp Asymmetry ◽  
The Standard Model ◽  
Doublet Model ◽  
Two Higgs Doublet Model ◽  
Cp Asymmetries

Abstract In this paper we investigate CP violation in charged decays of D meson. Particularly, we study the direct CP asymmetry of the Cabibbo favored non-leptonic $$D^+ \rightarrow {\bar{K}}^0 \pi ^+$$D+→K¯0π+ and the doubly Cabibbo-suppressed decay mode $$D^+ \rightarrow K^0 \pi ^+$$D+→K0π+ within standard model, two Higgs doublet model with generic Yukawa structure and left right symmetric models. In the standard model, we first derive the contributions from box and di-penguin diagrams contributing to their amplitudes which are relevant to the generation of the weak phases essential for non-vanishing direct CP violation. Then, we show that the generated phases are so tiny leading to null direct CP asymmetries of both decay modes. Regarding the two Higgs doublet model with generic Yukawa structure, after taking into account all constraints on the parameter space of the model, we show that the weak phases of the amplitudes can be enhanced compared to the standard model ones. However, the enhancement is still not enough to have sizable direct CP asymmetries. Finally, within left right symmetric models, we find that $$|A^{SM+LR}_{CP} (D^+ \rightarrow {\bar{K}}^0 \pi ^+)|\lesssim \mathcal {O}(10^{-3})$$|ACPSM+LR(D+→K¯0π+)|≲O(10-3) after respecting all relevant constraints on the parameter space of the model.

scholarly journals APPROXIMATE FLAVOR SYMMETRIES AT A GRAND UNIFICATION SCALE

1996 ◽  
Vol 11 (12) ◽  
pp. 965-971
Author(s):  
D. GÓMEZ DUMM
Keyword(s):  
Standard Model ◽  
Higgs Doublet ◽  
Grand Unification ◽  
Fermion Mass ◽  
Flavor Symmetries ◽  
Mass Matrices ◽  
The Standard Model ◽  
The Hierarchical Structure ◽  
Doublet Model ◽  
Two Higgs Doublet Model

We study the evolution of fermion mass matrices considering the hypothesis of approximate flavor symmetries (AFS) in the standard model and a two-Higgs-doublet model. We find that the hierarchical structure is not significantly altered by the running, hence the assumption of AFS is entirely compatible with a grand unification scenario.

ONE-LOOP CORRECTIONS TO WWγ AND WWZ VERTICES IN THE THDM

1995 ◽  
Vol 10 (22) ◽  
pp. 3169-3186
Author(s):  
H.B. BENAOUM ◽  
R. BOUAMRANE
Keyword(s):  
Standard Model ◽  
Magnetic Dipole ◽  
Form Factors ◽  
Electric Quadrupole ◽  
Higgs Doublet ◽  
Analytic Expressions ◽  
Doublet Model ◽  
Minimal Standard ◽  
The One ◽  
Two Higgs Doublet Model

The one-loop corrections to the three-boson vertices WWγ and WWZ are studied in the context of the minimal standard model (MSM) as well as the two-Higgs-doublet model (THDM). Analytic expressions of the magnetic dipole and electric quadrupole form factors are given and discussed as functions of various parameters.

scholarly journals Rare three-body decayt→chγ in the standard model and the two-Higgs doublet model

2006 ◽  
Vol 32 (4) ◽  
pp. 529-545 ◽  
Author(s):  
A Cordero-Cid ◽  
J L García-Luna ◽  
F Ramírez-Zavaleta ◽  
G Tavares-Velasco ◽  
J J Toscano
Keyword(s):  
Standard Model ◽  
Higgs Doublet ◽  
The Standard Model ◽  
Doublet Model ◽  
Three Body ◽  
Two Higgs Doublet Model
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