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.

CMS Pixel Detector Upgrade and Top Quark Pole Mass Determination
CMS Pixel Detector Upgrade and Top Quark Pole Mass Determination

Author: Simon Spannagel

Publisher: Springer

Published: 2017-08-01

Total Pages: 286

ISBN-13: 331958880X

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This thesis addresses two different topics, both vital for implementing modern high-energy physics experiments: detector development and data analysis. Providing a concise introduction to both the standard model of particle physics and the basic principles of semiconductor tracking detectors, it presents the first measurement of the top quark pole mass from the differential cross-section of tt+J events in the dileptonic tt decay channel. The first part focuses on the development and characterization of silicon pixel detectors. To account for the expected increase in luminosity of the Large Hadron Collider (LHC), the pixel detector of the compact muon solenoid (CMS) experiment is replaced by an upgraded detector with new front-end electronics. It presents comprehensive test beam studies conducted to verify the design and quantify the performance of the new front-end in terms of tracking efficiency and spatial resolution. Furthermore, it proposes a new cluster interpolation method, which utilizes the third central moment of the cluster charge distribution to improve the position resolution. The second part of the thesis introduces an alternative measurement of the top quark mass from the normalized differential production cross-sections of dileptonic top quark pair events with an additional jet. The energy measurement is 8TeV. Using theoretical predictions at next-to-leading order in perturbative Quantum Chromodynamics (QCD), the top quark pole mass is determined using a template fit method.

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

Author: Jan Kieseler

Publisher: Springer

Published: 2016-06-15

Total Pages: 172

ISBN-13: 3319400053

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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.

Physics at the Large Hadron Collider
Physics at the Large Hadron Collider

Author: Amitava Datta

Publisher: Springer Science & Business Media

Published: 2010-05-30

Total Pages: 260

ISBN-13: 8184892950

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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.