scholarly journals CP-ODD HIGGS BOSON PRODUCTION IN ASSOCIATION WITH NEUTRAL GAUGE BOSON IN HIGH ENERGY e+e- COLLISIONS

1999 ◽  
Vol 14 (30) ◽  
pp. 2093-2107 ◽  
Author(s):  
A. G. AKEROYD ◽  
A. ARHRIB ◽  
M. CAPDEQUI PEYRANÉRE
Keyword(s):  
Higgs Boson ◽  
Gauge Boson ◽  
Cross Sections ◽  
Top Quark ◽  
Higgs Doublet ◽  
High Energy ◽  
Loop Contribution ◽  
Neutral Gauge Boson ◽  
Associated Production ◽  
The One

We study the associated production of a CP-odd Higgs boson A0 with a neutral gauge boson (Z or photon) in high-energy e+e- collisions at the one-loop level in the framework of two Higgs doublet models (THDM). We find that in the small tan β regime, the top quark loop contribution is enhanced leading to significant cross-sections (about a few fb), while in the large tan β regime the cross-section does not attain observable rates.

EXTRA NEUTRAL GAUGE BOSON FROM THE 3-3-1 MODEL AND THE SPIN CORRECTION OF TOP QUARK PAIR PRODUCTION AT THE ILC

2009 ◽  
Vol 24 (16) ◽  
pp. 1307-1315 ◽  
Author(s):  
YAO-BEI LIU ◽  
XUE-LEI WANG
Keyword(s):  
Pair Production ◽  
Gauge Boson ◽  
Cross Sections ◽  
Top Quark ◽  
Z Boson ◽  
High Energy ◽  
Numerical Results ◽  
Spin Configuration ◽  
Neutral Gauge Boson ◽  
Quark Pairs

In the off-diagonal basis, we explore the effects of extra neutral gauge boson Z' predicted in two versions of SU (3)C × SU (3)L × U (1)X model on the spin configuration of the top quark pair production in the high energy linear e+e- collider (ILC). Our numerical results show that, the cross sections for the suppressed spin configurations can be enhanced with the effects of the Z' boson through the modification of the spin configuration by producing enough top quark pairs to be measured in the future ILC experiments, which provides the way to observe the effects of Z' predicted in the 3-3-1 model and discriminate the various versions of 3-3-1 model.

LEFT–RIGHT TWIN HIGGS MODEL AND THE SPIN CORRECTION OF TOP-QUARK PAIR PRODUCTION AT ILC

2009 ◽  
Vol 24 (23) ◽  
pp. 4261-4270 ◽  
Author(s):  
YAO-BEI LIU ◽  
SHUAI-WEI WANG
Keyword(s):  
Pair Production ◽  
Gauge Boson ◽  
Cross Sections ◽  
Top Quark ◽  
Center Of Mass ◽  
High Energy ◽  
Higgs Model ◽  
Spin Configuration ◽  
Neutral Gauge Boson ◽  
Quark Pairs

The left–right twin Higgs model predicts the existence of the new neutral gauge boson ZH. In the off-diagonal basis, we explore the effects of extra neutral gauge boson ZH on the spin configuration of the top-quark pair production in the high energy linear e+e- collider (ILC). We find that the new gauge boson ZH exchange can generate significant corrections to the differential cross-sections for the the [Formula: see text] and [Formula: see text] states. Furthermore, when the ZH mass MZH approaches the center-of-mass energy [Formula: see text], the cross-section resonance emerges. We expect that the effects of the new gauge boson ZH on the spin configurations of the top-quark pairs production might be observed in future ILC experiments.

scholarly journals tt̄H Coupling Measurement with the ATLAS Detector at the LHC

2018 ◽  
Vol 182 ◽  
pp. 02052
Author(s):  
Asma Hadef
Keyword(s):  
Higgs Boson ◽  
Cross Sections ◽  
Top Quark ◽  
High Energy Physics ◽  
Center Of Mass ◽  
High Energy ◽  
New Physics ◽  
Decay Modes ◽  
Center Of Mass Energy ◽  
Higgs Decay

The Higgs boson was discovered on the 4th of July 2012 with a mass around 125 GeV by ATLAS and CMS experiments at LHC. Determining the Higgs properties (production and decay modes, couplings,...) is an important part of the high-energy physics programme in this decade. A search for the Higgs boson production in association with a top quark pair (tt̄H) at ATLAS [1] is summarized in this paper at an unexplored center-of-mass energy of 13 TeV, which could allow a first direct measurement of the top quark Yukawa coupling and could reveal new physics. The tt̄H analysis in ATLAS is divided into 3 channels according to the Higgs decay modes: H → Hadrons, H → Leptons and H → Photons. The best-fit value of the ratio of observed and Standard Model cross sections of tt̄H production process, using 2015-2016 data and combining all tt̄H final states, is 1:8±0:7, corresponds to 2:8σ (1:8σ) observed (expected) significance.

scholarly journals ON THE ORIGIN OF APPROXIMATE CUSTODIAL SYMMETRY IN THE TWO-HIGGS DOUBLET MODEL

2009 ◽  
Vol 24 (30) ◽  
pp. 5587-5637 ◽  
Author(s):  
C. D. FROGGATT ◽  
R. NEVZOROV ◽  
H. B. NIELSEN ◽  
D. THOMPSON
Keyword(s):  
Higgs Boson ◽  
Top Quark ◽  
Higgs Doublet ◽  
High Energy ◽  
Boson Mass ◽  
Multiple Point ◽  
Large Set ◽  
Enhanced Production ◽  
Doublet Model ◽  
Two Higgs Doublet Model

We argue that the consistent implementation of the multiple point principle (MPP) in the general nonsupersymmetric two-Higgs doublet model (2HDM) can lead to a set of approximate global custodial symmetries that ensure CP conservation in the Higgs sector and the absence of flavor changing neutral currents (FCNC) in the considered model. In particular, the existence of a large set of degenerate vacua at some high energy scale Λ caused by the MPP can result in approximate U(1) and Z2 symmetries that suppress FCNC and CP-violating interactions in the 2HDM. We explore the renormalization group (RG) flow of the Yukawa and Higgs couplings within the MPP inspired 2HDM with approximate custodial symmetries and show that the solutions to the RG equations are focused near quasifixed points at low energies if the MPP scale Λ is relatively high. We study the Higgs spectrum and couplings near the quasifixed point at moderate values of tan β and compute a theoretical upper bound on the lightest Higgs boson mass. If Λ ≳ 1010 GeV the lightest CP-even Higgs boson is always lighter than 125 GeV. When the MPP scale is low, the mass of the lightest Higgs particle can reach 180–220 GeV while its coupling to the top quark can be significantly larger than in the SM, resulting in the enhanced production of Higgs bosons at the LHC. Other possible scenarios that appear as a result of the implementation of the MPP in the 2HDM are also discussed.

scholarly journals Higgs pair production in the CP-violating two-Higgs-doublet model

2017 ◽  
Vol 32 (34) ◽  
pp. 1746002 ◽  
Author(s):  
Ligong Bian ◽  
Ning Chen ◽  
Yun Jiang
Keyword(s):  
Higgs Boson ◽  
Pair Production ◽  
Cross Sections ◽  
Higgs Doublet ◽  
High Energy ◽  
Higgs Bosons ◽  
Mixing Angles ◽  
The Future ◽  
Doublet Model ◽  
Two Higgs Doublet Model

The SM-like Higgs pair production is discussed in the framework of the general CP-violating two-Higgs-doublet model, where we find that the CP-violating mixing angles can be related to the Higgs self-couplings. Therefore, the future experimental searches for Higgs boson pairs can be constrained by the improved precision of the electric dipole moment measurements. Based on a series of constraints of the SM-like Higgs boson signal fits, the perturbative unitarity and stability bounds to the Higgs potential, and the most recent LHC searches for heavy Higgs bosons, we suggest a set of benchmark models for the future high-energy collider searches for Higgs pair production. The [Formula: see text] colliders operating at [Formula: see text] are capable of measuring the Higgs cubic self-couplings of the benchmark models directly. We also estimate the cross sections of the resonance contributions to the Higgs pair productions for the benchmark models at the future LHC and SppC/FCC-hh runs.

scholarly journals Sensitivity to triple Higgs couplings via di-Higgs production in the 2HDM at $$e^+e^-$$ colliders

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
F. Arco ◽  
S. Heinemeyer ◽  
M. J. Herrero
Keyword(s):  
Higgs Boson ◽  
Cross Sections ◽  
Production Cross ◽  
Higgs Doublet ◽  
High Energy ◽  
Higgs Bosons ◽  
Higgs Production ◽  
Type I ◽  
Special Role ◽  
Enhanced Production

AbstractAn important task at future colliders is the investigation of the Higgs-boson sector. Here the measurement of the triple Higgs coupling(s) plays a special role. Based on previous analyses, within the framework of Two Higgs Doublet Models (2HDM) type I and II, we define and analyze several two-dimensional benchmark planes, that are over large parts in agreement with all theoretical and experimental constraints. For these planes we evaluate di-Higgs production cross sections at future high-energy $$e^+e^-$$ e + e - colliders, such as ILC or CLIC. We consider two different channels for the neutral di-Higgs pairs $$h_i h_j=hh,hH,HH,AA$$ h i h j = h h , h H , H H , A A : $$e^+e^- \rightarrow h_i h_j Z$$ e + e - → h i h j Z and $$e^+e^- \rightarrow h_i h_j \nu {{\bar{\nu }}}$$ e + e - → h i h j ν ν ¯ . In both channels the various triple Higgs-boson couplings contribute substantially. We find regions with a strong enhancement of the production channel of two SM-like light Higgs bosons and/or with very large production cross sections involving one light and one heavy or two heavy 2HDM Higgs bosons, offering interesting prospects for the ILC or CLIC. The mechanisms leading to these enhanced production cross sections are analyzed in detail. We propose the use of cross section distributions with the invariant mass of the two final Higgs bosons where the contributions from intermediate resonant and non-resonant BSM Higgs bosons play a crucial role. We outline which process at which center-of-mass energy would be best suited to probe the corresponding triple Higgs-boson couplings.

scholarly journals Mass Reconstruction of MSSM Higgs Boson

2019 ◽  
Vol 64 (8) ◽  
pp. 714
Author(s):  
T. V. Obikhod ◽  
I. A. Petrenko
Keyword(s):  
Experimental Data ◽  
Higgs Boson ◽  
Standard Model ◽  
Top Quark ◽  
Computer Programs ◽  
Higgs Bosons ◽  
Associated Production ◽  
The Standard Model ◽  
The Masses ◽  
Mass Reconstruction

The problems of the Standard Model, as well as questions related to Higgs boson properties led to the need to model the ttH associated production and the Higgs boson decay to a top quark pair within the MSSM model. With the help of computer programs MadGraph, Pythia, and Delphes and using the latest kinematic cuts taken from experimental data obtained at the LHC, we have predicted the masses of MSSM Higgs bosons, A and H.

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