The Search for Supersymmetry in Hadronic Final States Using Boosted Object Reconstruction

The Search for Supersymmetry in Hadronic Final States Using Boosted Object Reconstruction

Author: Giordon Stark

Publisher: Springer Nature

Published: 2020-03-13

Total Pages: 263

ISBN-13: 3030345483

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This thesis represents one of the most comprehensive and in-depth studies of the use of Lorentz-boosted hadronic final state systems in the search for signals of Supersymmetry conducted to date at the Large Hadron Collider. A thorough assessment is performed of the observables that provide enhanced sensitivity to new physics signals otherwise hidden under an enormous background of top quark pairs produced by Standard Model processes. This is complemented by an ingenious analysis optimization procedure that allowed for extending the reach of this analysis by hundreds of GeV in mass of these hypothetical new particles. Lastly, the combination of both deep, thoughtful physics analysis with the development of high-speed electronics for identifying and selecting these same objects is not only unique, but also revolutionary. The Global Feature Extraction system that the author played a critical role in bringing to fruition represents the first dedicated hardware device for selecting these Lorentz-boosted hadronic systems in real-time using state-of-the-art processing chips and embedded systems.


Searching for Squarks

Searching for Squarks

Author: Samuel Jones

Publisher: Springer Nature

Published: 2020-08-27

Total Pages: 235

ISBN-13: 3030542882

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This thesis focuses on searches for squarks with the ATLAS detector in "compressed" scenarios where the scalar top is very close in mass to the lightest supersymmetric particle. These models are theoretically appealing because the presence of a quasi-degenerate scalar top enhances the self-annihilation cross-section of the lightest supersymmetric particle, acting therefore as a regulator of the dark matter relic density. Two main analyses are presented: the first is a search for scalar tops decaying to charm quarks. The identification of jets originating from the charm quark is very challenging due to its short lifetime. The calibration of tools for charm-tagging has paved the way to measuring the decay of the Higgs boson to pairs of charm quarks. The second analysis presented is the development of a novel technique for reconstructing low momentum b-hadrons. This tool has enabled the ATLAS collaboration to explore topologies that were previously inaccessible.


Searches for the Supersymmetric Partner of the Top Quark, Dark Matter and Dark Energy at the ATLAS Experiment

Searches for the Supersymmetric Partner of the Top Quark, Dark Matter and Dark Energy at the ATLAS Experiment

Author: Nicolas Maximilian Köhler

Publisher: Springer Nature

Published: 2019-09-13

Total Pages: 264

ISBN-13: 3030259889

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Astrophysical observations implying the existence of Dark Matter and Dark Energy, which are not described by the Standard Model (SM) of particle physics, have led to extensions of the SM predicting new particles that could be directly produced at the Large Hadron Collider (LHC) at CERN. Based on 2015 and 2016 ATLAS proton-proton collision data, this thesis presents searches for the supersymmetric partner of the top quark, for Dark Matter, and for DarkEnergy, in signatures with jets and missing transverse energy. Muon detection is key to some of the most important LHC physics results, including the discovery of the Higgs boson and the measurement of its properties. The efficiency with which muons can be detected with the ATLAS detector is measured using Z boson decays. The performance of high-precision Monitored Drift Tube muon chambers under background rates similar to the ones expected for the High Luminosity-LHC is studied.


Calorimetry

Calorimetry

Author: R. Wigmans

Publisher: Oxford University Press

Published: 2000

Total Pages: 732

ISBN-13: 9780198502968

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Particle physics is the science that pursues the age-old quest for the innermost structure of matter and the fundamental interactions between its constituents. Modern experiments in this field rely increasingly on calorimetry, a detection techniques in which the particles of interest are absorbed in the detector. Calorimeters are very intricate instruments, their performance characteristics depend in subtle, sometimes counter-intuitive ways on design details. This book, written by one of the world's foremost experts, is the first comprehensive text on this topic. It provides a fundamental and systematic introduction, in which many intriguing calorimeter features are explained. It also describes the state of the art, both for what concerns the fundamental understanding of calorimetric particle detection and the actual detectors that have been or are being built and operated in experiments. In the last chapter, some landmark scientific discoveries in which calorimetry has played an important role are discussed. This book summarizes and puts into perspective work described in some 600 scientific papers, listed in the bibliography.


A Search for Displaced Leptons in the ATLAS Detector

A Search for Displaced Leptons in the ATLAS Detector

Author: Lesya Horyn

Publisher: Springer Nature

Published: 2022-02-07

Total Pages: 146

ISBN-13: 3030916723

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This thesis presents a search for long-lived particles decaying into displaced electrons and/or muons with large impact parameters. This signature provides unique sensitivity to the production of theoretical lepton-partners, sleptons. These particles are a feature of supersymmetric theories, which seek to address unanswered questions in nature. The signature searched for in this thesis is difficult to identify, and in fact, this is the first time it has been probed at the Large Hadron Collider (LHC). It covers a long-standing gap in coverage of possible new physics signatures. This thesis describes the special reconstruction and identification algorithms used to select leptons with large impact parameters and the details of the background estimation. The results are consistent with background, so limits on slepton masses and lifetimes in this model are calculated at 95% CL, drastically improving on the previous best limits from the Large Electron Positron Collider (LEP).


Particle Physics Reference Library

Particle Physics Reference Library

Author: Christian W. Fabjan

Publisher: Springer Nature

Published: 2020

Total Pages: 1083

ISBN-13: 3030353184

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This second open access volume of the handbook series deals with detectors, large experimental facilities and data handling, both for accelerator and non-accelerator based experiments. It also covers applications in medicine and life sciences. A joint CERN-Springer initiative, the "Particle Physics Reference Library" provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A, B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open access


Weak Scale Supersymmetry

Weak Scale Supersymmetry

Author: Howard Baer

Publisher: Cambridge University Press

Published: 2023-01-31

Total Pages: 557

ISBN-13: 1009289845

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This OA text develops the basic concepts of supersymmetry for experimental and phenomenological particle physicists and graduate students.


The Large Hadron Collider

The Large Hadron Collider

Author: Lyndon R. Evans

Publisher: EPFL Press

Published: 2009-01-01

Total Pages: 264

ISBN-13: 9782940222346

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Describes the technology and engineering of the Large Hadron collider (LHC), one of the greatest scientific marvels of this young 21st century. This book traces the feat of its construction, written by the head scientists involved, placed into the context of the scientific goals and principles.