scholarly journals PROBING THE ANOMALOUS COUPLINGS OF THE TOP QUARK WITH GLUON AT THE LHC AND TEVATRON

2013 ◽  
Vol 28 (37) ◽  
pp. 1350170 ◽  
Author(s):  
HODA HESARI ◽  
MOJTABA MOHAMMADI NAJAFABADI
Keyword(s):  
Production Rate ◽  
Cross Sections ◽  
Top Quark ◽  
Dipole Moments ◽  
Gluon Fusion ◽  
Fusion Process ◽  
Small Range ◽  
Anomalous Couplings ◽  
Text Production ◽  
Measured Ratio

In this paper, we study the sensitivity of the fraction of [Formula: see text] events arising from gluon–gluon fusion to the chromoelectric and chromomagnetic dipole moments (CEDM and CMDM) as well as the total and differential [Formula: see text] cross-sections at the LHC and Tevatron. The sensitivity of measured charged asymmetry at the LHC to CEDM and CMDM is also studied. We find that at the Tevatron and the LHC, nonzero values of CMDM could suppress the [Formula: see text] production rate. It is shown that the ratio of [Formula: see text] at the Tevatron is more sensitive to CEDM and CMDM than the LHC case. The presence of CEDM always increases the contribution of gluon–gluon fusion process in top pair rate at the Tevatron and LHC. Except for a small range of CMDM, the presence of CEDM and CMDM can increase the fraction of gluon–gluon fusion at the Tevatron and LHC. The measured ratio of [Formula: see text] at the Tevatron is used to derive bounds on the chromoelectric and chromomagnetic dipole moments as well as the total and differential [Formula: see text] cross-sections at the LHC and Tevatron, and the measured charged asymmetry at the LHC. The combination of [Formula: see text] and σ LHC provides stringent limits on CMDM and CEDM.

scholarly journals Studying the top quark via the W-gluon fusion process

1993 ◽  
Vol 306 (3-4) ◽  
pp. 386-390 ◽  
Author(s):  
Douglas O. Carlson ◽  
C.-P. Yuan
Keyword(s):  
Top Quark ◽  
Gluon Fusion ◽  
Fusion Process

scholarly journals Anomalous couplings in Higgs-boson pair production at approximate NNLO QCD

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Daniel de Florian ◽  
Ignacio Fabre ◽  
Gudrun Heinrich ◽  
Javier Mazzitelli ◽  
Ludovic Scyboz
Keyword(s):  
Higgs Boson ◽  
Pair Production ◽  
Top Quark ◽  
Gluon Fusion ◽  
Effective Field ◽  
Boson Pair ◽  
Anomalous Couplings ◽  
Boson Pair Production ◽  
Coupling Parameters ◽  
The Impact

Abstract We combine NLO predictions with full top-quark mass dependence with approximate NNLO predictions for Higgs-boson pair production in gluon fusion, including the possibility to vary coupling parameters within a non-linear Effective Field Theory framework containing five anomalous couplings for this process. We study the impact of the anomalous couplings on various observables, and present Higgs-pair invariant-mass distributions at seven benchmark points characterising different mhh shape types. We also provide numerical coefficients for the approximate NNLO cross section as a function of the anomalous couplings at $$ \sqrt{s} $$ s = 14 TeV.

scholarly journals Sensitivity measuring expected on the electromagnetic anomalous couplings in the tt̄γ vertex at the FCC-he

2020 ◽  
Vol 35 (28) ◽  
pp. 2050178
Author(s):  
M. Köksal ◽  
A. A. Billur ◽  
A. Gutiérrez-Rodríguez ◽  
M. A. Hernández-Ruíz
Keyword(s):  
Electron Beam ◽  
Dipole Moment ◽  
Top Quark ◽  
Dipole Moments ◽  
Production Cross ◽  
Anomalous Couplings ◽  
Decay Modes ◽  
Effective Lagrangian ◽  
Order Of Magnitude ◽  
Text Interaction

Starting from an effective Lagrangian for the [Formula: see text] interaction of the top-quark, we consider the electroweak production cross-section via charged current and through the [Formula: see text] signal. Further, we derive the sensitivity expected for the magnetic dipole moment [Formula: see text] and the electric dipole moment [Formula: see text] of the top-quark at the Future Circular Collider-hadron electron (FCC-he). We present our study for [Formula: see text], 10 TeV, [Formula: see text], 100, 300, 500, 1000 fb[Formula: see text], [Formula: see text] and [Formula: see text], 80%, [Formula: see text], respectively. We find that the sensitivity estimated on dipole moments of the top-quark is of the order of magnitude [Formula: see text] for both hadronic and leptonic decay modes of [Formula: see text]: [Formula: see text] and [Formula: see text] at 95% C.L. in the hadronic channel with unpolarized electron beam [Formula: see text]. Our results regarding the polarized electron beam for [Formula: see text] and [Formula: see text] are [Formula: see text], [Formula: see text] and [Formula: see text], [Formula: see text] at 95% C.L. in the hadronic channel. The corresponding results for the leptonic channel with [Formula: see text], 80% [Formula: see text] are [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text], [Formula: see text], respectively. The results for [Formula: see text] and [Formula: see text] in the leptonic channel are weaker than those corresponding to the hadronic channel by a factor of 0.75. Given these prospective sensitivities, the FCC-he is an alternative to study the anomalous couplings of the quark-top that would complement the studies of the LHC with cleaner environments.

scholarly journals Single-top and top-antitop cross sections

2018 ◽  
Vol 192 ◽  
pp. 00004
Author(s):  
Nikolaos Kidonakis
Keyword(s):  
Cross Sections ◽  
Top Quark ◽  
Production Cross ◽  
Anomalous Couplings ◽  
Total Cross Sections ◽  
Associated Production ◽  
Single Top ◽  
The Standard Model ◽  
Rapidity Distributions ◽  
Quark Transverse Momentum

I present high-order calculations, including soft-gluon corrections, for single-top and top-antitop production cross sections and differential distributions. For single-top production, results are presented for the three different channels in the Standard Model, for associated production with a charged Higgs, and for processes involving anomalous couplings. For top-antitop pair production, total cross sections and top-quark transverse-momentum and rapidity distributions are presented for various LHC energies.

scholarly journals Measurements of Higgs boson production cross sections and couplings in the diphoton decay channel at $$ \sqrt{\mathrm{s}} $$ = 13 TeV

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
◽  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
J. W. Andrejkovic ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Cross Sections ◽  
Top Quark ◽  
Production Cross ◽  
Vector Boson ◽  
Signal Strength ◽  
Gluon Fusion ◽  
Boson Production ◽  
Vector Boson Fusion ◽  
Higgs Boson Production

Abstract Measurements of Higgs boson production cross sections and couplings in events where the Higgs boson decays into a pair of photons are reported. Events are selected from a sample of proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV collected by the CMS detector at the LHC from 2016 to 2018, corresponding to an integrated luminosity of 137 fb−1. Analysis categories enriched in Higgs boson events produced via gluon fusion, vector boson fusion, vector boson associated production, and production associated with top quarks are constructed. The total Higgs boson signal strength, relative to the standard model (SM) prediction, is measured to be 1.12±0.09. Other properties of the Higgs boson are measured, including SM signal strength modifiers, production cross sections, and its couplings to other particles. These include the most precise measurements of gluon fusion and vector boson fusion Higgs boson production in several different kinematic regions, the first measurement of Higgs boson production in association with a top quark pair in five regions of the Higgs boson transverse momentum, and an upper limit on the rate of Higgs boson production in association with a single top quark. All results are found to be in agreement with the SM expectations.

PRECISIQN DETERMINATIONS OF ELECTROWEAK PARAMETERS FROM ep—COLLISIONS AT HERA—ENERGIES

1990 ◽  
Vol 05 (16) ◽  
pp. 3155-3169 ◽  
Author(s):  
A. WEBER
Keyword(s):  
Standard Model ◽  
Cross Sections ◽  
Gluon Fusion ◽  
Systematic Errors ◽  
Fusion Process ◽  
Model Parameters ◽  
Heavy Flavor ◽  
Parton Distributions ◽  
Quark Masses ◽  
Statistical Precision

We have studied HERA's capability of precisely measuring various parameters of the electroweak standard model. The analysis was performed in kinematical regions, x≥0.01 and x≥0.1, where systematic errors are expected to be under control. The statistical precision reachable for standard model parameters, extracted from R≡σ NC /σCC and NC asymmetries A for polarized e± beams, was estimated for both regions. Heavy flavor contributions, which amount up to 15% to the cross sections, were included via the boson-gluon fusion process. Furthermore the influence of various uncertainties (parton distributions, quark masses, σL/σT fixing input parameters) was estimated. For x≥0.01 the uncertainties due to parton densities are sizeable, the total rates (cross sections), however, increase strongly in contrast to the region x≥0.1.

scholarly journals Top quark anomalous couplings at the high-luminosity phase of the LHC

2019 ◽  
Vol 34 (18) ◽  
pp. 1950142 ◽  
Author(s):  
Frédéric Déliot ◽  
Miguel C. N. Fiolhais ◽  
António Onofre
Keyword(s):  
Cross Sections ◽  
Top Quark ◽  
W Boson ◽  
Production Cross ◽  
Hadron Collider ◽  
Center Of Mass ◽  
High Luminosity ◽  
Anomalous Couplings ◽  
Center Of Mass Energy ◽  
Single Top

The combination of the latest and most precise measurements of several top quark properties is presented in this paper in order to establish allowed regions on anomalous contributions to the Lorentz structure of the Wtb vertex. These measurements include single top production cross-sections, W boson helicity fractions and forward–backward asymmetries, both at Tevatron and at the Large Hadron Collider (LHC), up to a center-of-mass energy of 13 TeV. The results obtained at 95% Confidence Level (CL) for the top quark anomalous couplings are compared with the limits extracted from a combination that includes the expected measurements at the future High-Luminosity run of the LHC.

scholarly journals Boosting invisible Higgs boson searches by tagging a gluon jet for the gluon fusion process

2020 ◽  
Vol 102 (11) ◽  
Author(s):  
Won Sang Cho ◽  
Hyung Do Kim ◽  
Dongsub Lee
Keyword(s):  
Higgs Boson ◽  
Gluon Fusion ◽  
Fusion Process

scholarly journals Collinear expansion for color singlet cross sections

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Markus A. Ebert ◽  
Bernhard Mistlberger ◽  
Gherardo Vita
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
Gluon Fusion ◽  
Building Blocks ◽  
Color Singlet ◽  
Final State ◽  
Beam Function ◽  
Kinematic Limit ◽  
State Radiation

Abstract We demonstrate how to efficiently expand cross sections for color-singlet production at hadron colliders around the kinematic limit of all final state radiation being collinear to one of the incoming hadrons. This expansion is systematically improvable and applicable to a large class of physical observables. We demonstrate the viability of this technique by obtaining the first two terms in the collinear expansion of the rapidity distribution of the gluon fusion Higgs boson production cross section at next-to-next-to leading order (NNLO) in QCD perturbation theory. Furthermore, we illustrate how this technique is used to extract universal building blocks of scattering cross section like the N-jettiness and transverse momentum beam function at NNLO.

scholarly journals Heavy-flavor hadro-production with heavy-quark masses renormalized in the $$ \overline{\mathrm{MS}} $$, MSR and on-shell schemes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
M. V. Garzelli ◽  
L. Kemmler ◽  
S. Moch ◽  
O. Zenaiev
Keyword(s):  
Heavy Quark ◽  
Cross Sections ◽  
Top Quark ◽  
Quark Mass ◽  
Production Cross ◽  
Hadron Collider ◽  
Distribution Functions ◽  
Heavy Flavor ◽  
Parton Distribution Functions ◽  
Heavy Quark Mass

Abstract We present predictions for heavy-quark production at the Large Hadron Collider making use of the $$ \overline{\mathrm{MS}} $$ MS ¯ and MSR renormalization schemes for the heavy-quark mass as alternatives to the widely used on-shell renormalization scheme. We compute single and double differential distributions including QCD corrections at next-to-leading order and investigate the renormalization and factorization scale dependence as well as the perturbative convergence in these mass renormalization schemes. The implementation is based on publicly available programs, MCFM and xFitter, extending their capabilities. Our results are applied to extract the top-quark mass using measurements of the total and differential $$ t\overline{t} $$ t t ¯ production cross-sections and to investigate constraints on parton distribution functions, especially on the gluon distribution at low x values, from available LHC data on heavy-flavor hadro-production.

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