scholarly journals Search for New Physics with Top Quarks and Upgrade to the ATLAS Liquid Argon Calorimeter

2019 ◽  
Author(s):  
Stephanie Majewski
Keyword(s):  
2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Oliver Atkinson ◽  
Akanksha Bhardwaj ◽  
Christoph Englert ◽  
Vishal S. Ngairangbam ◽  
Michael Spannowsky

Abstract We devise an autoencoder based strategy to facilitate anomaly detection for boosted jets, employing Graph Neural Networks (GNNs) to do so. To overcome known limitations of GNN autoencoders, we design a symmetric decoder capable of simultaneously reconstructing edge features and node features. Focusing on latent space based discriminators, we find that such setups provide a promising avenue to isolate new physics and competing SM signatures from sensitivity-limiting QCD jet contributions. We demonstrate the flexibility and broad applicability of this approach using examples of W bosons, top quarks, and exotic hadronically-decaying exotic scalar bosons.


2013 ◽  
Vol 28 (08) ◽  
pp. 1330013 ◽  
Author(s):  
FRÉDÉRIC DÉLIOT ◽  
YVONNE PETERS ◽  
VERONICA SORIN

The heaviest known elementary particle, the top quark, was discovered in 1995 by the CDF and D0 collaborations at the Tevatron proton–antiproton collider at Fermilab. Since its discovery, a large program was set in motion by the CDF and D0 collaborations to characterize the production and decay properties of top quarks, and investigate their potential for searches of new phenomena beyond the standard model. During the past 20 years, new methods were developed and implemented to improve the measurements and searches for new physics in the top quark sector. This paper reviews the achievements and results obtained through studies of the top quark at the Tevatron.


2008 ◽  
Vol 23 (25) ◽  
pp. 4107-4124 ◽  
Author(s):  
TAO HAN

The LHC (Large Hadron Collider) will be a top-quark factory. With 80 million pairs of top quarks and an additional 34 million single tops produced annually at the designed high luminosity, the properties of this particle will be studied to a great accuracy. The fact that the top quark is the heaviest elementary particle in the Standard Model with a mass right at the electroweak scale makes it tempting to contemplate its role in electroweak symmetry breaking, as well as its potential as a window to unknown new physics at the TeV scale. We summarize the expectations for top-quark physics at the LHC, and outline new physics scenarios in which the top quark is crucially involved.


2020 ◽  
Vol 18 ◽  
pp. 66-77
Author(s):  
Abdeljali Habjial

The Standard Model production of four top quarks in the process pp --> tttt at a center-of-mass energy s1/2=13 Tev. The data collected by the ATLAS detector represents an impressive study potential, with an integrated luminosity of around 139 fb-1. In this manuscript, we present the production process of four top quarks at the LHC as well as some new physics models associated with this process. These models are studied in analysis carried. Some preliminary results are presented, in particular those of a new method for estimating background noise due to false leptons developed.


2014 ◽  
Author(s):  
Celine Catherine Degrande
Keyword(s):  

2019 ◽  
Vol 69 (1) ◽  
pp. 363-387 ◽  
Author(s):  
Pedro A.N. Machado ◽  
Ornella Palamara ◽  
David W. Schmitz

The Short-Baseline Neutrino (SBN) program consists of three liquid argon time-projection chamber detectors located along the Booster Neutrino Beam at Fermi National Accelerator Laboratory. Its main goals include searches for New Physics—particularly eV-scale sterile neutrinos, detailed studies of neutrino–nucleus interactions at the GeV energy scale, and the advancement of the liquid argon detector technology that will also be used in the DUNE/LBNF long-baseline neutrino experiment in the next decade. We review these science goals and the current experimental status of SBN.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  

Abstract Events containing one or more top quarks produced with additional prompt leptons are used to search for new physics within the framework of an effective field theory (EFT). The data correspond to an integrated luminosity of 41.5 fb−1 of proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC, collected by the CMS experiment in 2017. The selected events are required to have either two leptons with the same charge or more than two leptons; jets, including identified bottom quark jets, are also required, and the selected events are divided into categories based on the multiplicities of these objects. Sixteen dimension-six operators that can affect processes involving top quarks produced with additional charged leptons are considered in this analysis. Constructed to target EFT effects directly, the analysis applies a novel approach in which the observed yields are parameterized in terms of the Wilson coefficients (WCs) of the EFT operators. A simultaneous fit of the 16 WCs to the data is performed and two standard deviation confidence intervals for the WCs are extracted; the standard model expectations for the WC values are within these intervals for all of the WCs probed.


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