scholarly journals Searches for direct pair production of third generation squarks with the ATLAS detector

2018 ◽  
Vol 182 ◽  
pp. 02065
Author(s):  
Nicolas Köhler
Keyword(s):  
Large Hadron Collider ◽  
Standard Model ◽  
Pair Production ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Third Generation ◽  
Centre Of Mass ◽  
Mass Energy ◽  
The Third ◽  
Generation Squarks

Naturalness arguments for weak-scale supersymmetry favour supersymmetric partners of the third generation quarks with masses not too far from those of their Standard Model counterparts. Top or bottom squarks with masses less than or around one TeV can also give rise to direct pair production rates at the Large Hadron Collider (LHC) that can be observed in the data sample recorded by the ATLAS detector. This document presents recent ATLAS results from searches for direct top and bottom squark pair production considering both R-parity conserving and R-parity violating scenarios, using the data collected during the LHC Run 2 at a centre-of-mass energy of √s = 13 TeV.

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 Searches for Direct Pair Production of Third Generation Squarks with the ATLAS Detector

2018 ◽  
Vol 46 ◽  
pp. 1860057
Author(s):  
Federico Meloni
Keyword(s):  
Standard Model ◽  
Pair Production ◽  
Higgs Sector ◽  
Fine Tuning ◽  
Proton Collision ◽  
Third Generation ◽  
Proton Proton ◽  
Missing Transverse Momentum ◽  
Model Hierarchy ◽  
Generation Squarks

This document summarises recent ATLAS results for searches for third generation squarks using 36.1 [Formula: see text] of LHC proton-proton collision data collected at [Formula: see text] TeV. Despite the absence of experimental evidence, weak scale supersymmetry remains one of the best motivated and studied Standard Model extensions. Supersymmetry can naturally solve the Standard Model hierarchy problem by preventing a large fine-tuning in the Higgs sector: a typical natural SUSY spectrum contains light third generation squarks (stops and sbottoms). Both R-Parity conserving and R-Parity violating scenarios are considered. The searches involve final states including jets, missing transverse momentum, electrons or muons. Simplified models predicting pair production of third generation squarks have been excluded at 95% CL up to about one TeV in the most favourable scenarios.

scholarly journals HIGHLIGHTS FROM THE LHC

2013 ◽  
Vol 53 (A) ◽  
pp. 518-523
Author(s):  
Arno Straessner
Keyword(s):  
Large Hadron Collider ◽  
Standard Model ◽  
Hadron Collider ◽  
Centre Of Mass ◽  
Proton Proton ◽  
Exotic Particles ◽  
Proton Collisions ◽  
Total Luminosity ◽  
Future Data ◽  
Proton Proton Collisions

The Large Hadron Collider (LHC) and the two multi-purpose detectors, ATLAS and CMS, have been operated successfully at record centre-of-mass energies of 7 ÷ 8TeV. This paper presents the main physics results from proton–proton collisions based on a total luminosity of 2 × 5 fb<sup>−1</sup>. The most recent results from Standard Model measurements, Standard Model and MSSM Higgs searches, as well as searches for supersymmetric and exotic particles are reported. Prospects for ongoing and future data taking are presented.

scholarly journals AFTER THE STANDARD MODEL: NEW RESONANCES AT THE LHC

2009 ◽  
Vol 24 (01) ◽  
pp. 1-15 ◽  
Author(s):  
GUSTAAF BROOIJMANS
Keyword(s):  
Large Hadron Collider ◽  
Standard Model ◽  
Hadron Collider ◽  
Center Of Mass ◽  
New Physics ◽  
Mass Energy ◽  
High Expectations ◽  
Center Of Mass Energy ◽  
Energy Regime ◽  
The Standard Model

Experiments will soon start taking data at CERN's Large Hadron Collider (LHC) with high expectations for discovery of new physics phenomena. Indeed, the LHC's unprecedented center-of-mass energy will allow the experiments to probe an energy regime where the standard model is known to break down. Here, the experiments' capability to observe new resonances in various channels is reviewed.

scholarly journals Measurements of the Higgs H(125) boson at CMS

2018 ◽  
Vol 182 ◽  
pp. 02018
Author(s):  
Valeria Botta
Keyword(s):  
Higgs Boson ◽  
Large Hadron Collider ◽  
Hadron Collider ◽  
Top Quarks ◽  
Final States ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Associated Production ◽  
Cms Detector ◽  
Integrated Luminosity

The most recent measurements of the Higgs H(125) boson in several final states, including decays to bosons, fermions, and the associated production of a Higgs boson with top quarks, are reviewed. Results have been obtained analysing the protonproton collision data collected with the CMS detector at the Large Hadron Collider (LHC) in 2016, corresponding to an integrated luminosity of 35.9 fb-1 at a centre-of-mass energy of 13 TeV.

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