scholarly journals Top-quark pair production in association with a W± gauge boson in the POWHEG-BOX

2021 ◽  
Vol 103 (9) ◽  
Author(s):  
F. Febres Cordero ◽  
M. Kraus ◽  
L. Reina
Keyword(s):  
Pair Production ◽  
Gauge Boson ◽  
Top Quark

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 Top quark pair production near threshold: single/double distributions and mass determination

2020 ◽  
Vol 2020 (6) ◽  
Author(s):  
Wan-Li Ju ◽  
Guoxing Wang ◽  
Xing Wang ◽  
Xiaofeng Xu ◽  
Yongqi Xu ◽  
...  
Keyword(s):  
Pair Production ◽  
Top Quark ◽  
Mass Determination ◽  
Near Threshold

scholarly journals Search for pair production of third-generation scalar leptoquarks decaying into a top quark and a τ-lepton in pp collisions at $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Pair Production ◽  
Top Quark ◽  
Production Cross ◽  
Branching Fraction ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Third Generation ◽  
Final State ◽  
Generation Scalar ◽  
Scalar Leptoquarks

Abstract A search for pair production of third-generation scalar leptoquarks decaying into a top quark and a τ-lepton is presented. The search is based on a dataset of pp collisions at $$ \sqrt{s} $$ s = 13 TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. Events are selected if they have one light lepton (electron or muon) and at least one hadronically decaying τ -lepton, or at least two light leptons. In addition, two or more jets, at least one of which must be identified as containing b-hadrons, are required. Six final states, defined by the multiplicity and flavour of lepton candidates, are considered in the analysis. Each of them is split into multiple event categories to simultaneously search for the signal and constrain several leading backgrounds. The signal-rich event categories require at least one hadronically decaying τ-lepton candidate and exploit the presence of energetic final-state objects, which is characteristic of signal events. No significant excess above the Standard Model expectation is observed in any of the considered event categories, and 95% CL upper limits are set on the production cross section as a function of the leptoquark mass, for different assumptions about the branching fractions into tτ and bν. Scalar leptoquarks decaying exclusively into tτ are excluded up to masses of 1.43 TeV while, for a branching fraction of 50% into tτ, the lower mass limit is 1.22 TeV.

scholarly journals Optimising top-quark threshold scan at CLIC using genetic algorithm

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
K. Nowak ◽  
A.F. Żarnecki
Keyword(s):  
Genetic Algorithm ◽  
Pair Production ◽  
Top Quark ◽  
Quark Mass ◽  
Mass Measurement ◽  
Production Cross ◽  
Model Parameters ◽  
Top Quark Mass ◽  
Systematic Uncertainties ◽  
Pair Production Cross Section

Abstract One of the important goals at the future e+e− colliders is to measure the top-quark mass and width in a scan of the pair production threshold. However, the shape of the pair-production cross section at the threshold depends also on other model parameters, as the top Yukawa coupling, and the measurement is a subject to many systematic uncertainties. Presented in this work is the study of the top-quark mass determination from the threshold scan at CLIC. The most general approach is used with all relevant model parameters and selected systematic uncertainties included in the fit procedure. Expected constraints from other measurements are also taken into account. It is demonstrated that the top-quark mass can be extracted with precision of the order of 30 to 40 MeV, including considered systematic uncertainties, already for 100 fb−1 of data collected at the threshold. Additional improvement is possible, if the running scenario is optimised. With the optimisation procedure based on the genetic algorithm the statistical uncertainty of the mass measurement can be reduced by about 20%. Influence of the collider luminosity spectra on the expected precision of the measurement is also studied.

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