Top Quark Pair Production

Top Quark Pair Production PDF Author: Anna Christine Henrichs
Publisher: Springer Science & Business Media
ISBN: 3319014870
Category : Science
Languages : en
Pages : 231

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Book Description
Before any kind of new physics discovery could be made at the LHC, a precise understanding and measurement of the Standard Model of particle physics' processes was necessary. The book provides an introduction to top quark production in the context of the Standard Model and presents two such precise measurements of the production of top quark pairs in proton-proton collisions at a center-of-mass energy of 7 TeV that were observed with the ATLAS Experiment at the LHC. The presented measurements focus on events with one charged lepton, missing transverse energy and jets. Using novel and advanced analysis techniques as well as a good understanding of the detector, they constitute the most precise measurements of the quantity at that time.

Top Quark Pair Production

Top Quark Pair Production PDF Author: Anna Christine Henrichs
Publisher: Springer Science & Business Media
ISBN: 3319014870
Category : Science
Languages : en
Pages : 231

Get Book Here

Book Description
Before any kind of new physics discovery could be made at the LHC, a precise understanding and measurement of the Standard Model of particle physics' processes was necessary. The book provides an introduction to top quark production in the context of the Standard Model and presents two such precise measurements of the production of top quark pairs in proton-proton collisions at a center-of-mass energy of 7 TeV that were observed with the ATLAS Experiment at the LHC. The presented measurements focus on events with one charged lepton, missing transverse energy and jets. Using novel and advanced analysis techniques as well as a good understanding of the detector, they constitute the most precise measurements of the quantity at that time.

Search for tt̄H Production in the H → bb̅ Decay Channel

Search for tt̄H Production in the H → bb̅ Decay Channel PDF Author: Marcel Rieger
Publisher: Springer Nature
ISBN: 3030653803
Category : Science
Languages : en
Pages : 217

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Book Description
In 1964, a mechanism explaining the origin of particle masses was proposed by Robert Brout, François Englert, and Peter W. Higgs. 48 years later, in 2012, the so-called Higgs boson was discovered in proton-proton collisions recorded by experiments at the LHC. Since then, its ability to interact with quarks remained experimentally unconfirmed. This book presents a search for Higgs bosons produced in association with top quarks tt̄H in data recorded with the CMS detector in 2016. It focuses on Higgs boson decays into bottom quarks H → bb̅ and top quark pair decays involving at least one lepton. In this analysis, a multiclass classification approach using deep learning techniques was applied for the first time. In light of the dominant background contribution from tt̄ production, the developed method proved to achieve superior sensitivity with respect to existing techniques. In combination with searches in different decay channels, the presented work contributed to the first observations of tt̄H production and H → bb̅ decays.

Top-Quark Pair Production Cross Sections and Calibration of the Top-Quark Monte-Carlo Mass

Top-Quark Pair Production Cross Sections and Calibration of the Top-Quark Monte-Carlo Mass PDF Author: Jan Kieseler
Publisher: Springer
ISBN: 3319400053
Category : Science
Languages : en
Pages : 172

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Book Description
This thesis presents the first experimental calibration of the top-quark Monte-Carlo mass. It also provides the top-quark mass-independent and most precise top-quark pair production cross-section measurement to date. The most precise measurements of the top-quark mass obtain the top-quark mass parameter (Monte-Carlo mass) used in simulations, which are partially based on heuristic models. Its interpretation in terms of mass parameters used in theoretical calculations, e.g. a running or a pole mass, has been a long-standing open problem with far-reaching implications beyond particle physics, even affecting conclusions on the stability of the vacuum state of our universe. In this thesis, this problem is solved experimentally in three steps using data obtained with the compact muon solenoid (CMS) detector. The most precise top-quark pair production cross-section measurements to date are performed. The Monte-Carlo mass is determined and a new method for extracting the top-quark mass from theoretical calculations is presented. Lastly, the top-quark production cross-sections are obtained – for the first time – without residual dependence on the top-quark mass, are interpreted using theoretical calculations to determine the top-quark running- and pole mass with unprecedented precision, and are fully consistently compared with the simultaneously obtained top-quark Monte-Carlo mass.

Measurement of the Top Quark Mass in the Dilepton Final State Using the Matrix Element Method

Measurement of the Top Quark Mass in the Dilepton Final State Using the Matrix Element Method PDF Author: Alexander Grohsjean
Publisher: Springer Science & Business Media
ISBN: 364214070X
Category : Science
Languages : en
Pages : 155

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Book Description
The main pacemakers of scienti?c research are curiosity, ingenuity, and a pinch of persistence. Equipped with these characteristics a young researcher will be s- cessful in pushing scienti?c discoveries. And there is still a lot to discover and to understand. In the course of understanding the origin and structure of matter it is now known that all matter is made up of six types of quarks. Each of these carry a different mass. But neither are the particular mass values understood nor is it known why elementary particles carry mass at all. One could perhaps accept some small generic mass value for every quark, but nature has decided differently. Two quarks are extremely light, three more have a somewhat typical mass value, but one quark is extremely massive. It is the top quark, the heaviest quark and even the heaviest elementary particle that we know, carrying a mass as large as the mass of three iron nuclei. Even though there exists no explanation of why different particle types carry certain masses, the internal consistency of the currently best theory—the standard model of particle physics—yields a relation between the masses of the top quark, the so-called W boson, and the yet unobserved Higgs particle. Therefore, when one assumes validity of the model, it is even possible to take precise measurements of the top quark mass to predict the mass of the Higgs (and potentially other yet unobserved) particles.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 702

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Book Description


Search for Higgs Boson Pair Production in the bb̅ τ+ τ- Decay Channel

Search for Higgs Boson Pair Production in the bb̅ τ+ τ- Decay Channel PDF Author: Luca Cadamuro
Publisher: Springer
ISBN: 3030040550
Category : Science
Languages : en
Pages : 283

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Book Description
This thesis presents innovative contributions to the CMS experiment in the new trigger system for the restart of the LHC collisions in Run II, as well as original analysis methods and important results that led to official publications of the Collaboration. The author's novel reconstruction algorithms, deployed on the Field-Programmable Gate Arrays of the new CMS trigger architecture, have brought a gain of over a factor 2 in efficiency for the identification of tau leptons, with a very significant impact on important H boson measurements, such as its decays to tau lepton pairs and the search for H boson pair production. He also describes a novel analysis of HH → bb tautau, a high priority physics topic in a difficult channel. The original strategy, optimisation of event categories, and the control of the background have made the result one of the most sensitive concerning the self-coupling of the Higgs boson among all possible channels at the LHC.

Frontiers of Fundamental Physics and Physics Education Research

Frontiers of Fundamental Physics and Physics Education Research PDF Author: Burra G. Sidharth
Publisher: Springer Science & Business Media
ISBN: 331900297X
Category : Science
Languages : en
Pages : 586

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Book Description
In a knowledge-based society, research into fundamental physics plays a vital role not only in the enhancement of human knowledge but also in the development of new technology that affects everyday life.The international symposium series Frontiers of Fundamental Physics (FFP) regularly brings together eminent scholars and researchers working in various areas in physics to exchange expertise, ideas, results, and new research perspectives. The twelfth such symposium, FFP12, took place at the University of Udine, Italy, and covered diverse fields of research: astrophysics, high energy physics and particle physics, theoretical physics, gravitation and cosmology, condensed matter physics, statistical physics, computational physics, and mathematical physics. Importantly, it also devoted a great deal of attention to physics education research, teacher training in modern physics, and popularization of physics. The high scientific level of FFP12 was guaranteed by the careful selection made by scientific coordinators from among 250 submissions from 28 countries across the world. During the three days of the conference, nine general talks were delivered in plenary sessions, 29 invited talks were given in specific topic areas, and 59 oral presentations were made. This book presents a selection of the best contributions at FFP12 with the aim of acquainting readers with the most important recent advances in fundamental physics and in physics education and teacher development.

Physics at the Large Hadron Collider

Physics at the Large Hadron Collider PDF Author: Amitava Datta
Publisher: Springer Science & Business Media
ISBN: 8184892950
Category : Science
Languages : en
Pages : 260

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Book Description
In an epoch when particle physics is awaiting a major step forward, the Large Hydron Collider (LHC) at CERN, Geneva will soon be operational. It will collide a beam of high energy protons with another similar beam circulation in the same 27 km tunnel but in the opposite direction, resulting in the production of many elementary particles some never created in the laboratory before. It is widely expected that the LHC will discover the Higgs boson, the particle which supposedly lends masses to all other fundamental particles. In addition, the question as to whether there is some new law of physics at such high energy is likely to be answered through this experiment. The present volume contains a collection of articles written by international experts, both theoreticians and experimentalists, from India and abroad, which aims to acquaint a non-specialist with some basic issues related to the LHC. At the same time, it is expected to be a useful, rudimentary companion of introductory exposition and technical expertise alike, and it is hoped to become unique in its kind. The fact that there is substantial Indian involvement in the entire LHC endeavour, at all levels including fabrication, physics analysis procedures as well as theoretical studies, is also amply brought out in the collection.

Proceedings of the Fourth International Workshop on the Identification of Dark Matter

Proceedings of the Fourth International Workshop on the Identification of Dark Matter PDF Author: Neil John Curwen Spooner
Publisher: World Scientific
ISBN: 9812382372
Category : Technology & Engineering
Languages : en
Pages : 684

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Book Description
The objective of this workshop series is to assess the status of work attempting to identify what constitutes dark matter - in particular, to consider the techniques being used, how successful they are, and what new techniques are likely to improve prospects for identifying likely dark matter candidates in the future.

Fundamental Physics, Selected Topics On High Energy And Astroparticle Physics - Proceedings Of The 25th International Winter Meeting

Fundamental Physics, Selected Topics On High Energy And Astroparticle Physics - Proceedings Of The 25th International Winter Meeting PDF Author: M Aguilar-benitez
Publisher: World Scientific
ISBN: 9814544531
Category : Science
Languages : en
Pages : 376

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Book Description
This book contains review talks on many current topics in high energy particle physics and astroparticle physics, such as the status of precision tests of the Standard Model, tau and B physics at LEP, precision tests of QCD at LEP, WW physics and searches at LEP-2, heavy quark physics at the Tevatron collider, QCD studies at HERA, very high energy gamma astronomy, physics prospects at the LHC, physics prospects at linear colliders, and others. It also contains short status reports on several approved or planned experiments, namely DIRAC, HERA-B, AMS and ANTARES.