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.

scholarly journals Constraints on coloured scalars from global fits

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Otto Eberhardt ◽  
Víctor Miralles ◽  
Antonio Pich
Keyword(s):  
Top Quark ◽  
Scalar Potential ◽  
Higgs Doublet ◽  
Model Parameters ◽  
Simple Extension ◽  
Minimal Flavour Violation ◽  
Yukawa Couplings ◽  
Flavour Violation ◽  
The One ◽  
Potential Parameters

Abstract We consider a simple extension of the electroweak theory, incorporating one SU(2)L doublet of colour-octet scalars with Yukawa couplings satisfying the principle of minimal flavour violation. Using the HEPfit package, we perform a global fit to the available data, including all relevant theoretical constraints, and extract the current bounds on the model parameters. Coloured scalars with masses below 1.05 TeV are already excluded, provided they are not fermiophobic. The mass splittings among the different (charged and CP-even and CP-odd neutral) scalars are restricted to be smaller than 20 GeV. Moreover, for scalar masses smaller than 1.5 TeV, the Yukawa coupling of the coloured scalar multiplet to the top quark cannot exceed the one of the SM Higgs doublet by more than 80%. These conclusions are quite generic and apply in more general frameworks (without fine tunings). The theoretical requirements of perturbative unitarity and vacuum stability enforce relevant constraints on the quartic scalar potential parameters that are not yet experimentally tested.

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 Radiatively induced flavour violation in the general two-Higgs doublet model with Yukawa alignment

2010 ◽  
Vol 692 (3) ◽  
pp. 189-195 ◽  
Author(s):  
Carolin B. Braeuninger ◽  
Alejandro Ibarra ◽  
Cristoforo Simonetto
Keyword(s):  
Higgs Doublet ◽  
Flavour Violation ◽  
Doublet Model ◽  
Two Higgs Doublet Model

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 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 STUDY OF CP VIOLATION IN $\Lambda_c^+$ DECAY

2011 ◽  
Vol 26 (15) ◽  
pp. 2523-2535 ◽  
Author(s):  
XIAN-WEI KANG ◽  
HAI-BO LI ◽  
GONG-RU LU ◽  
ALAKABHA DATTA
Keyword(s):  
Angular Distribution ◽  
Cp Violation ◽  
Vector Meson ◽  
Higgs Doublet ◽  
New Physics ◽  
Angular Analysis ◽  
The Standard Model ◽  
Helicity Amplitudes ◽  
Doublet Model ◽  
Two Higgs Doublet Model

In this paper, we study CP violation in [Formula: see text] and [Formula: see text] decays, where B, P and V denote a light spin-½ baryon, pseudoscalar and a vector meson respectively. In these processes the T odd CP violating triple-product (TP) correlations are examined. The genuine CP violating observables which are composed of the helicity amplitudes occurring in the angular distribution are constructed. Experimentally, by performing a full angular analysis it is shown how one may extract the helicity amplitudes and then obtain the TP asymmetries. We estimate the TP asymmetries in [Formula: see text] decays to be negligible in the Standard Model making these processes an excellent place to look for new physics. Taking a two-Higgs doublet model, as an example of new physics, we show that large TP asymmetries are possible in these decays. Finally, we discuss how BES-III and super τ-charm experiments will be sensitive to these CP violating signals in [Formula: see text] decays.

scholarly journals Phenomenology of the partially aligned 2HDM with leptonic meson decays

2019 ◽  
Vol 34 (30) ◽  
pp. 1950198 ◽  
Author(s):  
A. Carrillo-Monteverde ◽  
S. Gómez-Ávila ◽  
R. Gómez-Rosas ◽  
L. López-Lozano ◽  
A. Rosado
Keyword(s):  
Higgs Doublet ◽  
New Physics ◽  
Tree Level ◽  
Flavor Symmetry ◽  
Leptonic Decays ◽  
Quark Sector ◽  
Leptonic Sector ◽  
Doublet Model ◽  
Free Parameters ◽  
Two Higgs Doublet Model

In this paper we present a phenomenological analysis of the Partially Aligned Two Higgs Doublet Model (PA-2HDM) by using leptonic decays of mesons and [Formula: see text]–[Formula: see text] mixing. We focus our attention in a scenario where the leading contribution to FCNC is given by the tree-level interaction with the light pseudoscalar [Formula: see text] ([Formula: see text] GeV). We show how an underlying flavor symmetry controls FCNC in the quark and lepton couplings with the pseudoscalar, without alignment between Yukawa matrices. Upper bounds on the free parameters are calculated in the context of the leptonic decays [Formula: see text] and [Formula: see text] and [Formula: see text] mixing. Also, our assumptions imply that bounds on New Physics contribution in the quark sector coming from [Formula: see text] mixing impose an upper bound on the parameters for the leptonic sector. Finally we give predictions of branching ratios for leptonic decay of mesons with FCNC and LFV.

scholarly journals THE EXCLUSIVE $\bar B \to\pi e^+ e^-$ AND $\bar B\to \rho e^+ e^-$ DECAYS IN THE TWO HIGGS DOUBLET MODEL WITH FLAVOR CHANGING NEUTRAL CURRENTS

1999 ◽  
Vol 14 (27) ◽  
pp. 4365-4393 ◽  
Author(s):  
E. O. ILTAN
Keyword(s):  
Branching Ratio ◽  
Higgs Doublet ◽  
Branching Ratios ◽  
New Physics ◽  
Tree Level ◽  
Efficient Tool ◽  
Flavor Changing ◽  
The Matrix ◽  
Doublet Model ◽  
Two Higgs Doublet Model

We present the leading logarithmic QCD corrections to the matrix element of the decay b→de+e- in the two Higgs doublet model with tree level flavor changing currents (model III). We continue studying the differential branching ratio and the CP-violating asymmetry for the exclusive decays B→πe+e- and B→ρe+e- and analysing the dependencies of these quantities on the selected model III parameters, ξU,D, including the leading logarithmic QCD corrections. Further, we present the forward–backward asymmetry of dileptons for the decay B→ρe+e- and discuss the dependencies to the model III parameters. We observe that there is a possibility to enhance the branching ratios and suppress the CP-violating effects for both decays in the framework of the model III. Therefore, the measurements of these quantities will be an efficient tool to search the new physics beyond the SM.

scholarly journals Reparameterization of the scalar potential in the two Higgs doublet model

2006 ◽  
Vol 47 (3) ◽  
pp. 785-790
Author(s):  
Rodolfo A. Diaz ◽  
Viviana Dionicio ◽  
R. Martinez
Keyword(s):  
Scalar Potential ◽  
Higgs Doublet ◽  
Doublet Model ◽  
Two Higgs Doublet Model

scholarly journals SIGNATURES OF NEW PHYSICS IN DILEPTONIC B-DECAYS

2006 ◽  
Vol 21 (12) ◽  
pp. 2617-2634 ◽  
Author(s):  
S. RAI CHOUDHURY ◽  
A. S. CORNELL ◽  
NAVEEN GAUR ◽  
G. C. JOSHI
Keyword(s):  
B Mesons ◽  
B Meson ◽  
Higgs Doublet ◽  
New Physics ◽  
Final State ◽  
Decay Modes ◽  
Leptonic Decays ◽  
The Standard Model ◽  
Doublet Model ◽  
Two Higgs Doublet Model

Leptonic decays of B-mesons are theoretically very clean probes for testing the Standard Model (SM) and possible physics beyond it. Amongst the various leptonic decays of the B-meson, the pure dileptonic decay B → ℓ+ ℓ- is very important, as this mode is helicity suppressed in the SM but can be substantially enhanced in some of the models beyond the SM, such as supersymmetric (SUSY) theories and the two Higgs doublet model (2HDM). Although the purely dileptonic decay mode is helicity suppressed in the SM its associated mode B → ℓ+ ℓ-γ does not have the same suppression, due to the presence of γ in the final state. In this paper we will also analyze the effects of enhanced Z-penguins on these two decay modes.

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