scholarly journals Top quark pair production at small transverse momentum in hadronic collisions

2013 ◽  
Vol 88 (7) ◽  
Author(s):  
Hai Tao Li ◽  
Chong Sheng Li ◽  
Ding Yu Shao ◽  
Li Lin Yang ◽  
Hua Xing Zhu
Keyword(s):  
Transverse Momentum ◽  
Pair Production ◽  
Top Quark ◽  
Hadronic Collisions

scholarly journals Search for top squark pair production using dilepton final states in $${\text {p}}{\text {p}}$$ collision data collected at $$\sqrt{s}=13\,\text {TeV} $$

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Pair Production ◽  
Top Quark ◽  
Transverse Mass ◽  
Final States ◽  
Top Squark ◽  
Missing Transverse Momentum ◽  
Charged Leptons ◽  
The Masses ◽  
Lower Limits

AbstractA search is presented for supersymmetric partners of the top quark (top squarks) in final states with two oppositely charged leptons (electrons or muons), jets identified as originating from $${\text {b}}$$ b quarks, and missing transverse momentum. The search uses data from proton-proton collisions at $$\sqrt{s}=13\,\text {TeV} $$ s = 13 TeV collected with the CMS detector, corresponding to an integrated luminosity of 137$$\,{\text {fb}}^{-1}$$ fb - 1 . Hypothetical signal events are efficiently separated from the dominant top quark pair production background with requirements on the significance of the missing transverse momentum and on transverse mass variables. No significant deviation is observed from the expected background. Exclusion limits are set in the context of simplified supersymmetric models with pair-produced lightest top squarks. For top squarks decaying exclusively to a top quark and a lightest neutralino, lower limits are placed at $$95\%$$ 95 % confidence level on the masses of the top squark and the neutralino up to 925 and 450$$\,\text {GeV}$$ GeV , respectively. If the decay proceeds via an intermediate chargino, the corresponding lower limits on the mass of the lightest top squark are set up to 850$$\,\text {GeV}$$ GeV for neutralino masses below 420$$\,\text {GeV}$$ GeV . For top squarks undergoing a cascade decay through charginos and sleptons, the mass limits reach up to 1.4$$\,\text {TeV}$$ TeV and 900$$\,\text {GeV}$$ GeV respectively for the top squark and the lightest neutralino.

scholarly journals NNLO soft function for top quark pair production at small transverse momentum

2018 ◽  
Vol 2018 (10) ◽  
Author(s):  
René Ángeles-Martínez ◽  
Michał Czakon ◽  
Sebastian Sapeta
Keyword(s):  
Transverse Momentum ◽  
Pair Production ◽  
Top Quark ◽  
Soft Function

scholarly journals Parton showers and matching uncertainties in top quark pair production with Herwig 7

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Kyle Cormier ◽  
Simon Plätzer ◽  
Christian Reuschle ◽  
Peter Richardson ◽  
Stephen Webster
Keyword(s):  
Pair Production ◽  
Top Quark ◽  
Hadron Collider ◽  
Event Generator ◽  
Leading Order ◽  
Large Hadron Collider Data ◽  
Quark Decays ◽  
Depth Study ◽  
Matching Schemes ◽  
Hadronic Collisions

Abstract We evaluate the theoretical uncertainties in next-to-leading order plus parton shower predictions for top quark pair production and decay in hadronic collisions. Our work is carried out using the Herwig  7 event generator and presents an in-depth study of variations in matching schemes with two systematically different shower algorithms, the traditional angular-ordered and alternative dipole shower. We also present all of the required extensions of the Herwig dipole shower algorithm to properly take into account quark mass effects, as well as its ability to perform top quark decays. The predictions are compared at parton level as well as to Large Hadron Collider data, including in the boosted regime. We find that the regions where predictions with a non-top-quark-specific tune differ drastically from data are plagued by large uncertainties which are consistent between our two shower and matching algorithms.

scholarly journals Transverse-momentum resummation for top-quark pair production at the LHC

2018 ◽  
Vol 2018 (11) ◽  
Author(s):  
Stefano Catani ◽  
Massimiliano Grazzini ◽  
Hayk Sargsyan
Keyword(s):  
Transverse Momentum ◽  
Pair Production ◽  
Top Quark

scholarly journals Search for new phenomena in final states with b-jets and missing transverse momentum in $$ \sqrt{\mathrm{s}} $$ = 13 TeV pp collisions with the ATLAS detector

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Pair Production ◽  
Atlas Detector ◽  
Final States ◽  
Proton Proton ◽  
Missing Transverse Momentum ◽  
The Standard Model ◽  
Proton Data ◽  
Identification Techniques ◽  
New Phenomena

Abstract The results of a search for new phenomena in final states with b-jets and missing transverse momentum using 139 fb−1 of proton-proton data collected at a centre-of-mass energy $$ \sqrt{s} $$ s = 13 TeV by the ATLAS detector at the LHC are reported. The analysis targets final states produced by the decay of a pair-produced supersymmetric bottom squark into a bottom quark and a stable neutralino. The analysis also seeks evidence for models of pair production of dark matter particles produced through the decay of a generic scalar or pseudoscalar mediator state in association with a pair of bottom quarks, and models of pair production of scalar third-generation down-type leptoquarks. No significant excess of events over the Standard Model background expectation is observed in any of the signal regions considered by the analysis. Bottom squark masses below 1270 GeV are excluded at 95% confidence level if the neutralino is massless. In the case of nearly mass-degenerate bottom squarks and neutralinos, the use of dedicated secondary-vertex identification techniques permits the exclusion of bottom squarks with masses up to 660 GeV for mass splittings between the squark and the neutralino of 10 GeV. These limits extend substantially beyond the regions of parameter space excluded by similar ATLAS searches performed previously.

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
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