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.

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 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.

scholarly journals Interplay of New Physics effects in (g − 2)ℓ and h → ℓ+ℓ− — lessons from SMEFT

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Svjetlana Fajfer ◽  
Jernej F. Kamenik ◽  
M. Tammaro
Keyword(s):  
Closed Operator ◽  
Higgs Doublet ◽  
New Physics ◽  
Effective Field ◽  
Tree Level ◽  
Electroweak Symmetry ◽  
Scalar Leptoquark ◽  
Doublet Model ◽  
The One ◽  
Two Higgs Doublet Model

Abstract We explore the interplay of New Physics (NP) effects in (g− 2)ℓ and h→ℓ+ℓ− within the Standard Model Effective Field Theory (SMEFT) framework, including one-loop Renormalization Group (RG) evolution of the Wilson coefficients as well as matching to the observables below the electroweak symmetry breaking scale. We include both the leading dimension six chirality flipping operators including a Higgs and SU(2)L gauge bosons as well as four-fermion scalar and tensor operators, forming a closed operator set under the SMEFT RG equations. We compare present and future experimental sensitivity to different representative benchmark scenarios. We also consider two simple UV completions, a Two Higgs Doublet Model and a single scalar LeptoQuark extension of the SM, and show how tree level matching to SMEFT followed by the one-loop RG evolution down to the electroweak scale can reproduce with high accuracy the (g−2)ℓ and h→ℓ+ℓ− contributions obtained by the complete one- and even two-loop calculations in the full models.

scholarly journals Detailed study of the Λb → Λcτν̄τ decay

2018 ◽  
Vol 33 (29) ◽  
pp. 1850169 ◽  
Author(s):  
E. Di Salvo ◽  
F. Fontanelli ◽  
Z. J. Ajaltouni
Keyword(s):  
Standard Model ◽  
Semileptonic Decay ◽  
Form Factors ◽  
Higgs Doublet ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Left Handed ◽  
The Standard Model ◽  
Analogous Formula ◽  
Two Higgs Doublet Model

We examine in detail the semileptonic decay [Formula: see text], which may confirm previous hints, from the analogous [Formula: see text] decay, of a new physics beyond the Standard Model. First of all, starting from rather general assumptions, we predict the partial width of the decay. Then we analyze the effects of five possible new physics interactions, adopting in each case five different form factors. In particular, for each term beyond the Standard Model, we find some constraints on the strength and phase of the coupling, which we combine with those found by other authors in analyzing the analogous semileptonic decays of [Formula: see text]. Our analysis involves some dimensionless quantities, substantially independent of the form factor, but which, owing to the constraints, turn out to be strongly sensitive to the kind of nonstandard interaction. We also introduce a criterion thanks to which one can discriminate among the various new physics terms: the left-handed current and the two-Higgs-doublet model appear privileged, with a neat preference for the former interaction. Finally, we suggest a differential observable that could, in principle, help to distinguish between the two cases.

scholarly journals Fingerprinting the contribution of colored scalars to the $$H^+ W^- Z(\gamma )$$ vertex

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Nabarun Chakrabarty ◽  
Indrani Chakraborty ◽  
Dilip Kumar Ghosh
Keyword(s):  
Scalar Potential ◽  
Form Factors ◽  
Higgs Doublet ◽  
New Physics ◽  
Model Parameters ◽  
Minimal Flavour Violation ◽  
Color Octet ◽  
Flavour Violation ◽  
Doublet Model ◽  
Two Higgs Doublet Model

AbstractColor-octet scalars arise in various Grand Unification scenarios and also in other models of new physics. They are also postulated for minimal flavour violation. Purely phenomenological imprints of such scalars are therefore worth looking at. Motivated by this, we perform a complete one-loop calculation of the $$H^+ \rightarrow W^+ Z (\gamma )$$ H + → W + Z ( γ ) decay in a two Higgs doublet model augmented by a color-octet $$SU(2)_L$$ S U ( 2 ) L scalar doublet. The computation is conveniently segregated into colorless and colored components. The color-octet part of the amplitude, being scaled by the color-factor, provides an overall enhancement to the form factors. Crucial constraints from perturbative unitarity, positivity of the scalar potential, oblique parameters, Higgs signal strengths and direct search of a charged Higgs and color-octet scalars are folded-in into the analysis. Sensitivity of the loop-induced $$H^+ \rightarrow W^+ Z (\gamma )$$ H + → W + Z ( γ ) vertex to other model parameters is elucidated. Finally, the prospect of observing a loop-induced $$H^+ \rightarrow W^+ Z (\gamma )$$ H + → W + Z ( γ ) interaction at the future hadronic collisions is also discussed.

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