scholarly journals Electroweak corrections to the fermionic decays of heavy Higgs states

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Florian Domingo ◽  
Sebastian Paßehr
Keyword(s):  
Standard Model ◽  
Scalar Fields ◽  
Higgs Doublet ◽  
New Physics ◽  
Higgs Bosons ◽  
Light Higgs Boson ◽  
Collider Phenomenology ◽  
The One ◽  
Three Body ◽  
Electroweak Corrections

Abstract Extensions of the standard model often come with additional, possibly electroweakly charged Higgs states, the prototypal example being the Two-Higgs-Doublet Model. While collider phenomenology does not exclude the possibility for some of these new scalar fields to be light, it is relatively natural to consider masses in the multi-TeV range, in which case the only remaining light Higgs boson automatically receives SM-like properties. The appearance of a hierarchy between the new-physics states and the electroweak scale then leads to sizable electroweak corrections, e. g. in the decays of the heavy Higgs bosons, which are dominated by effects of infrared type, namely Sudakov logarithms. Such radiative contributions obviously affect the two-body decays, but should also be paired with the radiation of electroweak gauge bosons (or lighter Higgs bosons) for a consistent picture at the one-loop order. Resummation of the leading terms is also relatively easy to achieve. We re-visit these questions in the specific case of the fermionic decays of heavy Higgs particles in the Next-to-Minimal Supersymmetric Standard Model, in particular pointing out the consequences of the three-body final states for the branching ratios of the heavy scalars.

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 IMPLICATION OF sin 2β FROM GLOBAL FIT AND B→J/ψKS

2001 ◽  
Vol 16 (28) ◽  
pp. 4547-4565 ◽  
Author(s):  
YUE-LIANG WU ◽  
YU-FENG ZHOU
Keyword(s):  
Standard Model ◽  
Higgs Doublet ◽  
New Physics ◽  
Current Data ◽  
Beyond The Standard Model ◽  
Flavor Violation ◽  
Flavor Changing ◽  
The Standard Model ◽  
Global Fit ◽  
The One

The measurement of sin 2β is discussed within and beyond the standard model. In the presence of new physics, the angle β extracted from the global fit (denoted by [Formula: see text]) and the one extracted from B→J/ψKS(denoted by βJ/ψ) are in general all different from the "true" angle β which is the weak phase of CKM matrix element [Formula: see text]. Possible new physics effects on the ratio [Formula: see text] is studied and parametrized in a most general form. It is shown that the ratio Rβmay provide a useful tool in probing new physics. The experimental value of Rβis obtained through an update of the global fit of the unitarity triangle with the latest data and found to be less than unity at 1σ level. The new physics effects on Rβfrom the models with minimum flavor violation (MFV) and the standard model with two-Higgs-doublet (S2HDM) are studied in detail. It is found that the MFV models seem to give a relative large value Rβ≥1. With the current data, this may indicate that this kind of new physics may be disfavored and alternative new physics with additional phases appears more relevant. As an illustration for models with additional phase beyond CKM phase, the S2HDM effects on Rβare studied and found to be easily coincide with the data due to the flavor changing neutral Higgs interaction.

scholarly journals Type-I 2HDM under the Higgs and electroweak precision measurements

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Ning Chen ◽  
Tao Han ◽  
Shuailong Li ◽  
Shufang Su ◽  
Wei Su ◽  
...  
Keyword(s):  
Standard Model ◽  
Higgs Doublet ◽  
New Physics ◽  
Higgs Bosons ◽  
Precision Measurements ◽  
Tree Level ◽  
Type I ◽  
Loop Level ◽  
The Standard Model ◽  
Parameter Ranges

Abstract We explore the extent to which future precision measurements of the Standard Model (SM) observables at the proposed Z-factories and Higgs factories may have impacts on new physics beyond the Standard Model, as illustrated by studying the Type-I Two-Higgs-doublet model (Type-I 2HDM). We include the contributions from the heavy Higgs bosons at the tree-level and at the one-loop level in a full model-parameter space. While only small tan β region is strongly constrained at tree level, the large tan β region gets constrained at loop level due to tan β enhanced tri-Higgs couplings. We perform a multiple variable χ2 fit with non-alignment and non-degenerate masses. We find that the allowed parameter ranges could be tightly constrained by the future Higgs precision measurements, especially for small and large values of tan β. Indirect limits on the masses of heavy Higgs bosons can be obtained, which can be complementary to the direct searches of the heavy Higgs bosons at hadron colliders. We also find that the expected accuracies at the Z-pole and at a Higgs factory are quite complementary in constraining mass splittings of heavy Higgs bosons. The typical results are | cos(β − α)| < 0.05, |∆mΦ| < 200 GeV, and tan β ≳ 0.3. The reaches from CEPC, Fcc-ee and ILC are also compared, for both Higgs and Z-pole precision measurements. Comparing to the Type-II 2HDM, the 95% C.L. allowed range of cos(β − α) is larger, especially for large values of tan β.

scholarly journals Naturalness implications within the two-real-scalar-singlet beyond the SM

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Jamal Ou Aali ◽  
Bouzid Manaut ◽  
Larbi Rahili ◽  
Souad Semlali
Keyword(s):  
Hadron Collider ◽  
Dimensional Regularization ◽  
Scalar Fields ◽  
New Physics ◽  
Higgs Bosons ◽  
Real Scalar ◽  
Stringent Constraint ◽  
The Standard Model ◽  
The One ◽  
Scalar Singlet

AbstractThe aim of this study is to investigate the quadratic divergences using dimensional regularization within the context of the Standard Model (SM) extended by two real scalar singlets (TRSM). This extension provides three neutral scalar fields that mix, after developing its VEVs, leading to three CP-even Higgs bosons, namely, $$h_1$$ h 1 , $$h_2$$ h 2 and $$h_3$$ h 3 , which would offer a wide phenomenology at the Large Hadron Collider (LHC), as reported recently. Furthermore, to fulfill the Veltman conditions for those three fields, we concentrate on the one-loop level ($$d_L=2$$ d L = 2 ) of dimensional regularization calculations, assuming $$R_{\xi }$$ R ξ Feynman–’t Hooft gauge-invariant, $$\xi =1$$ ξ = 1 . We show that the divergence cancellation could take place in the framework of the TRSM for the SM-like Higgs boson predicting a stringent constraint on the space parameters as well as the new physics (NP) scale, and yet remain consistent with current experimental measurements at 13 TeV.

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 The forgotten channels: charged Higgs boson decays to a W± and a non-SM-like Higgs boson

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Henning Bahl ◽  
Tim Stefaniak ◽  
Jonas Wittbrodt
Keyword(s):  
Higgs Boson ◽  
Higgs Sector ◽  
Higgs Doublet ◽  
Charged Higgs Boson ◽  
Higgs Bosons ◽  
Type I ◽  
Collider Phenomenology ◽  
Charged Higgs ◽  
Charged Higgs Bosons ◽  
Almost All

Abstract The presence of charged Higgs bosons is a generic prediction of multiplet extensions of the Standard Model (SM) Higgs sector. Focusing on the Two-Higgs-Doublet-Model (2HDM) with type I and lepton-specific Yukawa sectors, we discuss the charged Higgs boson collider phenomenology in the theoretically and experimentally viable parameter space. While almost all existing experimental searches at the LHC target the fermionic decays of charged Higgs bosons, we point out that the bosonic decay channels — especially the decay into a non-SM-like Higgs boson and a W boson — often dominate over the fermionic channels. Moreover, we revisit two genuine BSM effects on the properties of the discovered Higgs boson — the charged Higgs contribution to the diphoton rate and the Higgs decay to two light Higgs bosons — and their implication for the charged Higgs boson phenomenology. As main result of the present paper, we propose five two-dimensional benchmark scenarios with distinct phenomenological features in order to facilitate the design of dedicated LHC searches for charged Higgs bosons decaying into a W boson and a light, non-SM-like Higgs boson.

scholarly journals Exploration of Extended Higgs Sectors with Run-2 Proton–Proton Collision Data at the LHC

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2144
Author(s):  
Arnaud Ferrari ◽  
Nikolaos Rompotis
Keyword(s):  
Standard Model ◽  
Higgs Sector ◽  
Scalar Fields ◽  
Higgs Bosons ◽  
Proton Collision ◽  
Complex Scalar ◽  
Proton Proton ◽  
The Standard Model ◽  
Extended Higgs Sectors ◽  
Proton Proton Collision

One doublet of complex scalar fields is the minimal content of the Higgs sector in order to achieve spontaneous electroweak symmetry breaking and, in turn, to generate the masses of fundamental particles in the Standard Model. However, several theories beyond the Standard Model predict a nonminimal Higgs sector and introduce additional singlets, doublets or even higher-order weak isospin representations, thereby yielding additional Higgs bosons. With its high proton–proton collision energy (13 TeV during Run-2), the Large Hadron Collider opens a new window towards the exploration of extended Higgs sectors. This review article summarises the current state-of-the-art experimental results recently obtained in searches for new neutral and charged Higgs bosons with a partial or full Run-2 dataset.

scholarly journals The history of the muon (g-2) experiments

2019 ◽  
Author(s):  
B. Lee Roberts
Keyword(s):  
Standard Model ◽  
Quantum Electrodynamics ◽  
National Laboratory ◽  
New Physics ◽  
Brookhaven National Laboratory ◽  
Muon Decay ◽  
Higgs Bosons ◽  
The Standard Model ◽  
History Of ◽  
First Time

I discuss the history of the muon (g-2)(g−2) measurements, beginning with the Columbia-Nevis measurement that observed parity violation in muon decay, and also measured the muon gg-factor for the first time, finding g_\mu=2gμ=2. The theoretical (Standard Model) value contains contributions from quantum electrodynamics, the strong interaction through hadronic vacuum polarization and hadronic light-by-light loops, as well as the electroweak contributions from the WW, ZZ and Higgs bosons. The subsequent experiments, first at Nevis and then with increasing precision at CERN, measured the muon anomaly a_\mu = (g_\mu-2)/2aμ=(gμ−2)/2 down to a precision of 7.3 parts per million (ppm). The Brookhaven National Laboratory experiment E821 increased the precision to 0.54 ppm, and observed for the first time the electroweak contributions. Interestingly, the value of a_\muaμ measured at Brookhaven appears to be larger than the Standard Model value by greater than three standard deviations. A new experiment, Fermilab E989, aims to improve on the precision by a factor of four, to clarify whether this result is a harbinger of new physics entering through loops, or from some experimental, statistical or systematic issue.

scholarly journals The “96 GeV excess” at the LHC

2021 ◽  
pp. 2142018
Author(s):  
T. Biekötter ◽  
M. Chakraborti ◽  
S. Heinemeyer
Keyword(s):  
Higgs Boson ◽  
Decay Mode ◽  
Higgs Doublet ◽  
Higgs Bosons ◽  
Final State ◽  
Light Higgs Boson ◽  
Doublet Model ◽  
Higgs Boson Search

The CMS collaboration reported an intriguing [Formula: see text] (local) excess at 96 GeV in the light Higgs-boson search in the diphoton decay mode. This mass coincides with a [Formula: see text] (local) excess in the [Formula: see text] final state at LEP. We briefly review the proposed combined interpretations for the two excesses. In more detail, we review the interpretation of this possible signal as the lightest Higgs boson in the 2 Higgs Doublet Model with an additional real Higgs singlet (N2HDM). We show which channels have the best prospects for the discovery of additional Higgs bosons at the upcoming Run 3 of the LHC.

scholarly journals Higgs searches beyond the Standard Model

2014 ◽  
Vol 31 ◽  
pp. 1460288 ◽  
Author(s):  
R. Mankel ◽  
Keyword(s):  
Standard Model ◽  
Higgs Sector ◽  
Higgs Doublet ◽  
Higgs Bosons ◽  
Supersymmetric Model ◽  
Beyond The Standard Model ◽  
Model Interpretation ◽  
The Standard Model ◽  
Extended Higgs Sectors ◽  
Minimal Supersymmetric Model

While the existence of a Higgs boson with a mass near 125 GeV has been clearly established, the detailed structure of the entire Higgs sector is yet unclear. Besides the Standard Model interpretation, various possibilities for extended Higgs sectors are being considered. The minimal supersymmetric extension (MSSM) features two Higgs doublets resulting in five physical Higgs bosons, which are subject to direct searches. Alternatively, more generic Two-Higgs Doublet models (2HDM) are used for the interpretation of results. The Next-to-Minimal Supersymmetric Model (NMSSM) has a more complex Higgs sector with seven physical states. Also exotic Higgs bosons decaying to invisible final states are considered. This article summarizes recent findings based on results from collider experiments.

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