scholarly journals Top-quark-antiquark production in association with a photon in the electron-muon channel at a centre-of-mass energy of 13 TeV with the ATLAS detector

2021 ◽  
Author(s):  
John Kamal Rizk Meshreki ◽  
Keyword(s):  
Top Quark ◽  
Atlas Detector ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Muon Channel

scholarly journals Hunting New Physics with ATLAS

2018 ◽  
Vol 182 ◽  
pp. 02089
Author(s):  
Vasiliki A. Mitsou ◽  
Keyword(s):  
Extra Dimension ◽  
New Physics ◽  
Atlas Detector ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Gauge Bosons

Highlights from recent new physics searches with the ATLAS detector at the CERN LHC are presented in this paper. They include searches for extra-dimension models, compositeness, new gauge bosons, supersymmetry, among others. Results are based on analyses of pp collision data recorded at a centre-of-mass energy of 13 TeV.

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 lepton-flavour-violating decays of the $Z$ boson into a $\tau$-lepton and a light lepton with the ATLAS detector

2019 ◽  
Author(s):  
Wing Sheung Chan
Keyword(s):  
Atlas Detector ◽  
Beyond The Standard Model ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Lepton Flavour Violation ◽  
Lepton Flavor ◽  
Upper Limits ◽  
Flavour Violation ◽  
8 Tev ◽  
Lepton Flavour

Lepton flavour violation in the charged lepton sector is an unambiguous signal of physics beyond the Standard Model. Searches for lepton flavour violation in decays of the ZZ boson with the ATLAS detector is reported, focusing on decays into an electron or muon and a hadronically decaying \tauτ-lepton, using pppp collisions data with a centre-of-mass energy of 13 TeV. Upper limits on the branching ratios of lepton-flavor-violating decays are set at the 95% confidence level: \mathcal{B}(Z\to e\tau) < 5.8\times10^{-5}ℬ(Z→eτ)<5.8×10−5 and \mathcal{B}(Z\to \mu\tau) < 2.4\times10^{-5}ℬ(Z→μτ)<2.4×10−5. When combined with a previous ATLAS result based on pppp collisions data with a centre-of-mass energy of 8 TeV, an upper limit of \mathcal{B}(Z\to \mu\tau) < 1.3\times10^{-5}ℬ(Z→μτ)<1.3×10−5 is obtained.

scholarly journals Measurement of $$K_S^0$$ and $$\Lambda ^0$$ production in $$t \bar{t}$$ dileptonic events in pp collisions at $$\sqrt{s} =$$ 7 TeV with the ATLAS detector

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
O. Abdinov ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Final States ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Proton Proton ◽  
Proton Collisions ◽  
Strange Particles ◽  
Proton Proton Collisions

AbstractMeasurements of $$K_S^0$$KS0 and $$\Lambda ^0$$Λ0 production in $$t\bar{t}$$tt¯ final states have been performed. They are based on a data sample with integrated luminosity of 4.6 $$\mathrm {fb}^{-1}$$fb-1 from proton–proton collisions at a centre-of-mass energy of 7 TeV, collected in 2011 with the ATLAS detector at the Large Hadron Collider. Neutral strange particles are separated into three classes, depending on whether they are contained in a jet, with or without a b-tag, or not associated with a selected jet. The aim is to look for differences in their main kinematic distributions. A comparison of data with several Monte Carlo simulations using different hadronisation and fragmentation schemes, colour reconnection models and different tunes for the underlying event has been made. The production of neutral strange particles in $$t\bar{t}$$tt¯ dileptonic events is found to be well described by current Monte Carlo models for $$K_S^0$$KS0 and $$\Lambda ^0$$Λ0 production within jets, but not for those produced outside jets.

scholarly journals Search for pair production of scalar leptoquarks decaying into first- or second-generation leptons and top quarks in proton–proton collisions at $$\sqrt{s}$$ = 13 TeV with the ATLAS detector

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Pair Production ◽  
Top Quark ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Large Radius ◽  
Proton Proton ◽  
Proton Collisions ◽  
Muon Channel ◽  
Scalar Leptoquarks ◽  
Proton Proton Collisions

AbstractA search for pair production of scalar leptoquarks, each decaying into either an electron or a muon and a top quark, is presented. This is the first leptoquark search using ATLAS data to investigate top-philic cross-generational couplings that could provide explanations for recently observed anomalies in B meson decays. This analysis targets high leptoquark masses which cause the decay products of each resultant top quark to be contained within a single high-$$p_{\mathrm {T}}$$ p T large-radius jet. The full Run 2 dataset is exploited, consisting of $$139~\hbox {fb}^{-1}$$ 139 fb - 1 of data collected from proton–proton collisions at $$\sqrt{s}=13~\mathrm {TeV}$$ s = 13 TeV from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. In the absence of any significant deviation from the background expectation, lower limits on the leptoquark masses are set at $$1480~\mathrm {GeV}$$ 1480 GeV and $$1470~\mathrm {GeV}$$ 1470 GeV for the electron and muon channel, respectively.

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