ATLAS Measurements of the Higgs Boson Coupling to the Top Quark in the Higgs to Diphoton Decay Channel
ATLAS Measurements of the Higgs Boson Coupling to the Top Quark in the Higgs to Diphoton Decay Channel

Author: Jennet Elizabeth Dickinson

Publisher: Springer Nature

Published: 2021-11-16

Total Pages: 233

ISBN-13: 3030863689

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During Run 2 of the Large Hadron Collider, the ATLAS experiment recorded proton-proton collision events at 13 TeV, the highest energy ever achieved in a collider. Analysis of this dataset has provided new opportunities for precision measurements of the Higgs boson, including its interaction with the top quark. The Higgs-top coupling can be directly probed through the production of a Higgs boson in association with a top-antitop quark pair (ttH). The Higgs to diphoton decay channel is among the most sensitive for ttH measurements due to the excellent diphoton mass resolution of the ATLAS detector and the clean signature of this decay. Event selection criteria were developed using novel Machine Learning techniques to target ttH events, yielding a precise measurement of the ttH cross section in the diphoton channel and a 6.3 $\sigma$ observation of the ttH process in combination with other decay channels, as well as stringent limits on CP violation in the Higgs-top coupling.

Theoretical Studies on Extended Higgs Sectors Towards Future Precision Measurements
Theoretical Studies on Extended Higgs Sectors Towards Future Precision Measurements

Author: Masashi Aiko

Publisher: Springer Nature

Published: 2023-05-20

Total Pages: 268

ISBN-13: 9819913241

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This book investigates the physics of the discovered Higgs boson and additional Higgs bosons in the extended Higgs models which includes higher-order quantum corrections. While the 125 GeV Higgs boson was discovered, the structure of the Higgs sector is still a mystery. Since the Higgs sector determines the concrete realization of the Higgs mechanism, the study of its nature is one of the central interests in current and future high-energy physics. The book begins with a review of the standard model and the two-Higgs doublet model, which is one of the representatives of the extended Higgs models. Subsequently, we discuss the studies of the two-Higgs doublet model at the lowest order of perturbation. Following the lowest-order analysis, we study the higher-order electroweak corrections in Higgs physics. After reviewing the renormalization procedure and the higher-order corrections in the decays of the discovered Higgs boson, we discuss the higher-order corrections in the Higgs strahlung process from an electron-positron collision, the decays of the additional charged and CP-odd Higgs bosons in the two-Higgs doublet model. From the series of these studies, it is found that the nature of the Higgs sector can be widely investigated by future collider experiments.

Electroweak Physics at the LHC
Electroweak Physics at the LHC

Author: Matthias U. Mozer

Publisher: Springer

Published: 2016-03-24

Total Pages: 121

ISBN-13: 3319303813

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The book discusses the recent experimental results obtained at the LHC that involve electroweak bosons. The results are placed into an appropriate theoretical and historical context. The work pays special attention to the rising subject of hadronically decaying bosons with high boosts, documenting the state-of-the-art identification techniques and highlighting typical results. The text is not limited to electroweak physics in the strict sense, but also discusses the use of electroweak vector-bosons as tool in the study of other subjects in particle physics, such as determinations of the proton structure or the search for new exotic particles. The book is particularly well suited for graduate students, starting their thesis work on topics that involve electroweak bosons, as the book provides a comprehensive description of phenomena observable at current accelerators as well as a summary of the most relevant experimental techniques.

Looking Inside Jets
Looking Inside Jets

Author: Simone Marzani

Publisher: Springer

Published: 2019-05-11

Total Pages: 210

ISBN-13: 3030157091

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This concise primer reviews the latest developments in the field of jets. Jets are collinear sprays of hadrons produced in very high-energy collisions, e.g. at the LHC or at a future hadron collider. They are essential to and ubiquitous in experimental analyses, making their study crucial. At present LHC energies and beyond, massive particles around the electroweak scale are frequently produced with transverse momenta that are much larger than their mass, i.e., boosted. The decay products of such boosted massive objects tend to occupy only a relatively small and confined area of the detector and are observed as a single jet. Jets hence arise from many different sources and it is important to be able to distinguish the rare events with boosted resonances from the large backgrounds originating from Quantum Chromodynamics (QCD). This requires familiarity with the internal properties of jets, such as their different radiation patterns, a field broadly known as jet substructure. This set of notes begins by providing a phenomenological motivation, explaining why the study of jets and their substructure is of particular importance for the current and future program of the LHC, followed by a brief but insightful introduction to QCD and to hadron-collider phenomenology. The next section introduces jets as complex objects constructed from a sequential recombination algorithm. In this context some experimental aspects are also reviewed. Since jet substructure calculations are multi-scale problems that call for all-order treatments (resummations), the bases of such calculations are discussed for simple jet quantities. With these QCD and jet physics ingredients in hand, readers can then dig into jet substructure itself. Accordingly, these notes first highlight the main concepts behind substructure techniques and introduce a list of the main jet substructure tools that have been used over the past decade. Analytic calculations are then provided for several families of tools, the goal being to identify their key characteristics. In closing, the book provides an overview of LHC searches and measurements where jet substructure techniques are used, reviews the main take-home messages, and outlines future perspectives.

Search for New Heavy Charged Bosons and Measurement of High-Mass Drell-Yan Production in Proton—Proton Collisions
Search for New Heavy Charged Bosons and Measurement of High-Mass Drell-Yan Production in Proton—Proton Collisions

Author: Markus Zinser

Publisher: Springer

Published: 2018-09-25

Total Pages: 386

ISBN-13: 3030006506

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This book presents two analyses, the first of which involves the search for a new heavy charged gauge boson, a so-called W' boson. This new gauge boson is predicted by some theories extending the Standard Model gauge group to solve some of its conceptual problems. Decays of the W' boson in final states with a lepton (l± = e± , μ±) and the corresponding (anti-)neutrino are considered. Data collected by the ATLAS experiment in 2015 at a center of mass energy of √s =13 TeV is used for the analysis. In turn, the second analysis presents a measurement of the double-differential cross section of the process pp->Z/gamma^* + X -> l^+l^- + X, including a gamma gamma induced contribution, at a center of mass energy of sqrt{s} = 8 TeV. The measurement is performed in an invariant mass region of 116 GeV to 1500 GeV as a function of invariant mass and absolute rapidity of the l^+l^-- pair, and as a function of invariant mass and pseudorapidity separation of the l^+l^-- pair. The data analyzed was recorded by the ATLAS experiment in 2012 and corresponds to an integrated luminosity of 20.3/fb. It is expected that the measured cross sections are sensitive to the PDFs at very high values of the Bjorken-x scaling variable, and to the photon structure of the proton.

The God Particle
The God Particle

Author: Leon M. Lederman

Publisher: Houghton Mifflin Harcourt

Published: 2006

Total Pages: 452

ISBN-13: 9780618711680

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A fascinating tour of particle physics from Nobel Prize winner Leon Lederman. At the root of particle physics is an invincible sense of curiosity. Leon Lederman embraces this spirit of inquiry as he moves from the Greeks' earliest scientific observations to Einstein and beyond to chart this unique arm of scientific study. His survey concludes with the Higgs boson, nicknamed the God Particle, which scientists hypothesize will help unlock the last secrets of the subatomic universe, quarks and all--it's the dogged pursuit of this almost mystical entity that inspires Lederman's witty and accessible history.

Lepton Photon Interactions At High Energies (Lepton Photon 2017) - Proceedings Of The 28th International Symposium
Lepton Photon Interactions At High Energies (Lepton Photon 2017) - Proceedings Of The 28th International Symposium

Author: Wei Wang

Publisher: World Scientific

Published: 2020-02-27

Total Pages: 576

ISBN-13: 9811207410

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The latest of the 'Lepton Photon' symposium, one of the well-established series of meetings in the high-energy physics community, was successfully organized at the South Campus of Sun Yat-sen University, Guangzhou, China, from August 7-12, 2017, where physicists around the world gathered to discuss the latest advancements in the research field.This proceedings volume of the Lepton Photon 2017 collects contributions by the plenary session speakers and the posters' presenters, which cover the latest results in particle physics, nuclear physics, astrophysics, cosmology, and plans for future facilities.

Higgs boson potential at colliders: status and perspectives
Higgs boson potential at colliders: status and perspectives

Author: Biagio Di Micco

Publisher: Roma TrE-Press

Published: 2020-12-18

Total Pages: 281

ISBN-13:

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Questo documento riassume lo stato attuale degli ricerche studi, teorici e sperimentali, sulla produzione di coppie di bosoni di Higgs, e sui vincoli, sia diretti che indiretti, al valore del termine di auto-interazione del bosone di Higgs, con l’intento di servire da referenza per i prossimi anni. Il documento discute lo stato degli studi teorici, includendo le più recenti stime della sezione di produzione di coppie di bosoni di Higgs, sviluppi sulle teorie di campo efficaci, e studi su specifici scenari di nuova fisica che possono contribuire alla produzione di due bosoni di Higgs. Sono presentati i più recenti risultati sperimentali sulle ricerche di coppie di bosoni di Higgs e sui limiti diretti e indiretti al termine di auto-interazione, ottenuti al Large Hadron Collider di Ginevra, con una panoramica delle tecniche sperimentali. Infine, sono discusse le capacità dei collisionatori futuri di determinare il termine di auto-interazione del bosone di Higgs. Questo lavoro è iniziato come raccolta di contributi della conferenza “Di-Higgs ai Colliders”, che ha avuto luogo a Fermilab dal 4 al 9 settembre 2018, ma gli argomenti discussi vanno al di là di quelli presentati alla conferenza, includendo ulteriori sviluppi.

Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like?
Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like?

Author: Roman Pasechnik

Publisher: Frontiers Media SA

Published: 2020-09-03

Total Pages: 180

ISBN-13: 2889639908

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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.

Advances in Jet Substructure at the LHC
Advances in Jet Substructure at the LHC

Author: Roman Kogler

Publisher: Springer Nature

Published: 2021-05-10

Total Pages: 287

ISBN-13: 3030728587

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This book introduces the reader to the field of jet substructure, starting from the basic considerations for capturing decays of boosted particles in individual jets, to explaining state-of-the-art techniques. Jet substructure methods have become ubiquitous in data analyses at the LHC, with diverse applications stemming from the abundance of jets in proton-proton collisions, the presence of pileup and multiple interactions, and the need to reconstruct and identify decays of highly-Lorentz boosted particles. The last decade has seen a vast increase in our knowledge of all aspects of the field, with a proliferation of new jet substructure algorithms, calculations and measurements which are presented in this book. Recent developments and algorithms are described and put into the larger experimental context. Their usefulness and application are shown in many demonstrative examples and the phenomenological and experimental effects influencing their performance are discussed. A comprehensive overview is given of measurements and searches for new phenomena performed by the ATLAS and CMS Collaborations. This book shows the impressive versatility of jet substructure methods at the LHC.