Multi-Boson Interactions at the Run 1 LHC.

Multi-Boson Interactions at the Run 1 LHC.
Author:
Publisher:
Total Pages:
Release: 2016
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ISBN:

This review article covers results on the production of all possible electroweak boson pairs and 2-to-1 vector boson fusion (VBF) at the CERN Large Hadron Collider (LHC) in proton-proton collisions at a center-of-mass energy of 7 TeV and 8 TeV. The data was taken between 2010 and 2012. Limits on anomalous triple gauge couplings (aTGCs) then follow. In addition, data on electroweak triple gauge boson production and 2-to-2 vector boson scattering (VBS) yield limits on anomalous quartic gauge boson couplings (aQGCs). The LHC hosts two general purpose experiments, ATLAS and CMS, which both have reported limits on aTGCs and aQGCs which are herein summarized. The interpretation of these limits in terms of an effective field theory (EFT) is reviewed, and recommendations are made for testing other types of new physics using multi-gauge boson production.

Quark Confinement and the Hadron Spectrum V

Quark Confinement and the Hadron Spectrum V
Author: N. Brambilla
Publisher: World Scientific
Total Pages: 551
Release: 2003
Genre: Technology & Engineering
ISBN: 981238393X

This book provides an update on our understanding of strong interaction, with theoretical and experimental highlights included. It is divided into five sections. The first section is devoted to the investigations into and the latest results on the mechanism of quark confinement. The second and third sections focus respectively on light and heavy quarks (effective field theories, Schwinger-Dyson approach and lattice QCD results). The fourth section deals with the deconfinement mechanism and quark-gluon plasma formation signals. The last section presents highlights of experiments, new physics beyond QCD, and nonperturbative approaches in other theories (strings and SUSY) that may be useful in QCD.

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
Total Pages: 386
Release: 2018-09-25
Genre: Science
ISBN: 3030006506

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.

Looking Inside Jets

Looking Inside Jets
Author: Simone Marzani
Publisher: Springer
Total Pages: 205
Release: 2019-05-11
Genre: Science
ISBN: 3030157091

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.

Introduction to High Energy Physics

Introduction to High Energy Physics
Author: Donald H. Perkins
Publisher: Cambridge University Press
Total Pages: 454
Release: 2000-04-13
Genre: Science
ISBN: 1139643371

This highly-regarded text provides a comprehensive introduction to modern particle physics. Extensively rewritten and updated, this 4th edition includes developments in elementary particle physics, as well as its connections with cosmology and astrophysics. As in previous editions, the balance between experiment and theory is continually emphasised. The stress is on the phenomenological approach and basic theoretical concepts rather than rigorous mathematical detail. Short descriptions are given of some of the key experiments in the field, and how they have influenced our thinking. Although most of the material is presented in the context of the Standard Model of quarks and leptons, the shortcomings of this model and new physics beyond its compass (such as supersymmetry, neutrino mass and oscillations, GUTs and superstrings) are also discussed. The text includes many problems and a detailed and annotated further reading list.

Two Gauge Boson Physics at Future Colliders

Two Gauge Boson Physics at Future Colliders
Author:
Publisher:
Total Pages: 17
Release: 1988
Genre:
ISBN:

Electroweak unification suggests that there should be WW and ZZ physics analogous to [gamma][gamma] physics. Indeed, WW and ZZ collisions will provide an opportunity to search for the Higgs boson at future high energy colliders. Cross sections in the picobarn range are predicted for Higgs boson production at the proposed 40-TeV SSC. While other states may be produced by WW and ZZ collisions, it is the Higgs boson that looms as the most attractive objective. 31 refs., 5 figs.

Towards Higher Theoretical Precision for Electroweak Boson Production with B-jets at Hadron Colliders

Towards Higher Theoretical Precision for Electroweak Boson Production with B-jets at Hadron Colliders
Author: Diogenes Alberto Figueroa
Publisher:
Total Pages: 0
Release: 2021
Genre: Particles (Nuclear physics)
ISBN:

Processes involving the production of electroweak gauge bosons($W, Z, \gamma$) or a Higgs boson with $b$ jets play a very important role in stress testing the Standard Model and constitute major backgrounds in most searches of new physics beyond the Standard Model at present and future colliders. Given the unprecedented experimental precision that will be reached bythe Large Hadron Collider (LHC) experiments during the upcoming Run 3 and the high-luminosity upgrade (HL-LHC), improving the accuracy of theoretical predictions to reach the few-percent level becomes crucial to the success of their physics program. Besides accounting for QCD quantum corrections, this implies including electroweak quantum effects, $b$-quark mass effects, and effects due to the off-shellness of the final-state boson decaying into leptons or quarks, as well as revisiting approximations that enters in the evolution of a high-energy collision into final-state jets of hadrons. In this thesis we develop a general formalism (massive dipoles and massive 5 flavor scheme) to systematically account for $b$-quark mass effects at all stages, from the $b$-quark parton densities in the initial-state protons to the matching of $b$ quarks from the hard scattering to the final-state hadrons via parton shower. Formal results form this thesis have been implemented in the\texttt{Madisqe} framework to allow the general calculation of Standard Model cross sections including the first order of QCD and electroweak corrections and accounting for full $b$-quark mass effects. Furthermore, they have been used to improve the efficiency and numerical stability of \texttt{NLOX}, a public domain framework for the automated calculation of one-loop Standard Model scattering amplitudes. As a particularly interesting study case, we present in this thesisthe case of $Z+b$ jets. The production of a $Z$ boson with bottom quarks can probe both the fundamental properties of $b$ quarks as constituents of hadrons and hadron jets, and represents one of the major backgrounds to precision measurements of Higgs-boson couplings in $ZH (H\rightarrow b\bar{b}$) associated production as well as in many searches of new physics. In this thesis, we study in particulat the impact of EW corrections and $b$-quark mass effects on total and differential rates for $Z+b$ jets at the LHC.