A Collider Search for Dark Matter Produced in Association with a Higgs Boson with the CMS Detector at the 13 TeV LHC
A Collider Search for Dark Matter Produced in Association with a Higgs Boson with the CMS Detector at the 13 TeV LHC

Author: Dustin Ray Burns

Publisher:

Published: 2017

Total Pages:

ISBN-13: 9780355151343

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The study presented in this dissertation is a search for dark matter produced in 13 TeV proton-proton collisions at the Large Hadron Collider (LHC) using 35.9 fb−1 of data collected in 2016 with the Compact Muon Solenoid (CMS) detector. Dark matter escapes the detector without interacting, resulting in a large imbalance of transverse momentum, which can be observed when a Higgs boson is tagged in the opposite direction. A variety of models which motivate a dark matter and Higgs interaction are discussed. The experimental signature of these models is called mono-Higgs. In this search, the Higgs is produced primarily from gluon fusion and decays to four leptons via two Z bosons (H → ZZ → 4l). In addition to observing the Higgs in the four-lepton final state, an extensive study of missing transverse energy (MET) is required to search for the mono-Higgs signature. A background model is developed for the Standard Model processes that result in the same final state as the signal, then a counting experiment is performed in an optimized signal region. There is no evidence for an excess of events in the signal region above the backgrounds, so cross section limits are set for two kinematically distinct signal models.

Particle Physics Reference Library
Particle Physics Reference Library

Author: Herwig Schopper

Publisher: Springer Nature

Published: 2020

Total Pages: 632

ISBN-13: 3030382079

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This first open access volume of the handbook series contains articles on the standard model of particle physics, both from the theoretical and experimental perspective. It also covers related topics, such as heavy-ion physics, neutrino physics and searches for new physics beyond the standard model. 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

Discovery Of The Higgs Boson
Discovery Of The Higgs Boson

Author: Aleandro Nisati

Publisher: World Scientific

Published: 2016-08-26

Total Pages: 470

ISBN-13: 981442546X

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The recent observation of the Higgs boson has been hailed as the scientific discovery of the century and led to the 2013 Nobel Prize in physics. This book describes the detailed science behind the decades-long search for this elusive particle at the Large Electron Positron Collider at CERN and at the Tevatron at Fermilab and its subsequent discovery and characterization at the Large Hadron Collider at CERN. Written by physicists who played leading roles in this epic search and discovery, this book is an authoritative and pedagogical exposition of the portrait of the Higgs boson that has emerged from a large number of experimental measurements. As the first of its kind, this book should be of interest to graduate students and researchers in particle physics.

Electroweak Physics at the Large Hadron Collider with the ATLAS Detector
Electroweak Physics at the Large Hadron Collider with the ATLAS Detector

Author: Elodie Resseguie

Publisher: Springer Nature

Published: 2020-11-03

Total Pages: 336

ISBN-13: 3030570169

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This thesis discusses searches for electroweakly produced supersymmetric partners of the gauge and the Higgs bosons (gauginos and higgsinos) decaying to multiple leptons, using pp collisions at sqrt(s) = 13 TeV. The thesis presents an in-depth study of multiple searches, as well as the first 13 TeV cross section measurement for the dominant background in these searches, WZ production. Two searches were performed using 36.1/fb of data: the gaugino search, which makes use of a novel kinematic variable, and the higgsino search, which produced the first higgsino limits at the LHC. A search using 139/fb of data makes use of a new technique developed in this thesis to cross check an excess of data above the background expectation in a search using a Recursive Jigsaw Reconstruction technique. None of the searches showed a significant excess of data, and limits were expanded with respect to previous results. These searches will benefit from the addition of luminosity during HL-LHC; however, the current detector will not be able to withstand the increase in radiation. Electronics for the detector upgrade are tested and irradiated to ensure their performance.

Search for Exotic Higgs Boson Decays to Merged Diphotons
Search for Exotic Higgs Boson Decays to Merged Diphotons

Author: Michael Andrews

Publisher: Springer Nature

Published: 2023-03-02

Total Pages: 193

ISBN-13: 3031250915

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This book describes the first application at CMS of deep learning algorithms trained directly on low-level, “raw” detector data, or so-called end-to-end physics reconstruction. Growing interest in searches for exotic new physics in the CMS collaboration at the Large Hadron Collider at CERN has highlighted the need for a new generation of particle reconstruction algorithms. For many exotic physics searches, sensitivity is constrained not by the ability to extract information from particle-level data but by inefficiencies in the reconstruction of the particle-level quantities themselves. The technique achieves a breakthrough in the reconstruction of highly merged photon pairs that are completely unresolved in the CMS detector. This newfound ability is used to perform the first direct search for exotic Higgs boson decays to a pair of hypothetical light scalar particles H→aa, each subsequently decaying to a pair of highly merged photons a→yy, an analysis once thought impossible to perform. The book concludes with an outlook on potential new exotic searches made accessible by this new reconstruction paradigm.

Future Of The Large Hadron Collider, The: A Super-accelerator With Multiple Possible Lives
Future Of The Large Hadron Collider, The: A Super-accelerator With Multiple Possible Lives

Author: Oliver Bruning

Publisher: World Scientific

Published: 2023-08-08

Total Pages: 455

ISBN-13: 9811280193

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The Large Hadron Collider (LHC) is the highest energy collider ever built. It resides near Geneva in a tunnel 3.8m wide, with a circumference of 26.7km, which was excavated in 1983-1988 to initially house the electron-positron collider LEP. The LHC was approved in 1995, and it took until 2010 for reliable operation. By now, a larger set of larger integrated luminosities have been accumulated for physics analyses in the four collider experiments: ATLAS, CMS, LHCb and ALICE.The LHC operates with an extended cryogenic plant, using a multi-stage injection system comprising the PS and SPS accelerators (still in use for particle physics experiments at lower energies). The beams are guided by 1232 superconducting high field dipole magnets.Intense works are underway in preparation of the High Luminosity LHC, aimed at upgrading the LHC and detectors for collecting ten times more luminosity, and extending the collider life to the early 2040's. So far, the (HL-)LHC project represents a cumulation of around one hundred thousand person-years of innovative work by technicians, engineers, and physicists from all over the world; probably the largest scientific effort ever in the history of humanity. The book is driven by the realisation of the unique value of this accelerator complex and by the recognition of the status of high energy physics, described by a Standard Model — which still leaves too many questions unanswered to be the appropriate theory of elementary particles and their interactions.Following the Introduction are: three chapters which focus on the initial decade of operation, leading to the celebrated discovery of the Higgs Boson, on the techniques and physics of the luminosity upgrade, and finally on major options - of using the LHC in a concurrent, power economic, electron-hadron scattering mode, when upgraded to higher energies or eventually as an injector for the next big machine. The various technical and physics chapters, provided by 61 authors, characterise the fascinating opportunities the LHC offers for the next two decades ahead (possibly longer), with the goal to substantially advance our understanding of nature.

The Physics Associated with Neutrino Masses
The Physics Associated with Neutrino Masses

Author: Diego Aristizabal Sierra

Publisher: Frontiers Media SA

Published: 2020-01-13

Total Pages: 293

ISBN-13: 2889633519

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This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Collider
Collider

Author: Paul Halpern

Publisher: Turner Publishing Company

Published: 2009-07-17

Total Pages: 257

ISBN-13: 047048621X

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An accessible look at the hottest topic in physics and the experiments that will transform our understanding of the universe The biggest news in science today is the Large Hadron Collider, the world's largest and most powerful particle-smasher, and the anticipation of finally discovering the Higgs boson particle. But what is the Higgs boson and why is it often referred to as the God Particle? Why are the Higgs and the LHC so important? Getting a handle on the science behind the LHC can be difficult for anyone without an advanced degree in particle physics, but you don't need to go back to school to learn about it. In Collider, award-winning physicist Paul Halpern provides you with the tools you need to understand what the LHC is and what it hopes to discover. Comprehensive, accessible guide to the theory, history, and science behind experimental high-energy physics Explains why particle physics could well be on the verge of some of its greatest breakthroughs, changing what we think we know about quarks, string theory, dark matter, dark energy, and the fundamentals of modern physics Tells you why the theoretical Higgs boson is often referred to as the God particle and how its discovery could change our understanding of the universe Clearly explains why fears that the LHC could create a miniature black hole that could swallow up the Earth amount to a tempest in a very tiny teapot "Best of 2009 Sci-Tech Books (Physics)"-Library Journal "Halpern makes the search for mysterious particles pertinent and exciting by explaining clearly what we don't know about the universe, and offering a hopeful outlook for future research."-Publishers Weekly Includes a new author preface, "The Fate of the Large Hadron Collider and the Future of High-Energy Physics" The world will not come to an end any time soon, but we may learn a lot more about it in the blink of an eye. Read Collider and find out what, when, and how.

A Search for New Physics in Events with a Leptonically Decaying Z Boson and a Large Transverse Momentum Imbalance with the CMS Detector at the LHC
A Search for New Physics in Events with a Leptonically Decaying Z Boson and a Large Transverse Momentum Imbalance with the CMS Detector at the LHC

Author: Nicholas Charles Smith

Publisher:

Published: 2018

Total Pages: 0

ISBN-13:

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A search for new physics in events with a leptonically decaying Z boson and a large transverse momentum imbalance in proton-proton collisions collected at sqrt(s) = 13 TeV in 2016 with the Compact Muon Solenoid detector at the Large Hadron Collider is presented. The results of this search are interpreted in terms of a simplified model of dark matter production via spin-0 or spin-1 mediators, a scenario with a standard-model-like Higgs boson produced in association with the Z boson and decaying invisibly, a model of unparticle production, and a model with large extra spatial dimensions. No significant deviations from the background expectations are found, and limits are set on relevant model parameters, significantly extending the results previously achieved in this channel.

Search for Dark Matter Coupled to the Higgs Boson at the Large Hadron Collider
Search for Dark Matter Coupled to the Higgs Boson at the Large Hadron Collider

Author: Jue Chen

Publisher:

Published: 2020

Total Pages:

ISBN-13:

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This work presents the search for Dark Matter particles associated with the Higgs Boson decaying into a b b-bar quark pair. The dark matter search result is based on proton-proton collision data collected at a center-of-mass energy of 13 TeV by the ATLAS detector during Run II. The results are interpreted in the context of a simplified model (Z'-2HDM) which describes the interaction of dark matter and standard model particles via new heavy mediator particles. The new powerful Higgs tagging techniques, which exploit the jet substructure and heavy flavor information to a large extent, are developed to improve the search sensitivity of the search. The target physics signals are signature with an optimized search region and interpreted with background estimation result statistically.