Top Quark Physics At Hadron Colliders

This will be a required acquisition text for academic libraries. More than ten years after its discovery, still relatively little is known about the top quark, the heaviest known elementary particle. This extensive survey summarizes and reviews top-quark physics based on the precision measurements at the Fermilab Tevatron Collider, as well as examining in detail the sensitivity of these experiments to new physics. Finally, the author provides an overview of top quark physics at the Large Hadron Collider.

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.

Publisher Description

The top quark is by far the heaviest known fundamental particle with a mass nearing that of a gold atom. Because of this strikingly high mass, the top quark has several unique properties and might play an important role in electroweak symmetry breaking—the mechanism that gives all elementary particles mass. Creating top quarks requires access to very high energy collisions, and at present only the Tevatron collider at Fermilab is capable of reaching these energies. Until now, top quarks have only been observed produced in pairs via the strong interaction. At hadron colliders, it should also be possible to produce single top quarks via the electroweak interaction. Studies of single top quark production provide opportunities to measure the top quark spin, how top quarks mix with other quarks, and to look for new physics beyond the standard model. Because of these interesting properties, scientists have been looking for single top quarks for more than 15 years. This thesis presents the first discovery of single top quark production. It documents one of the flagship measurements of the D0 experiment, a collaboration of more than 600 physicists from around the world. It describes first observation of a physical process known as “single top quark production”, which had been sought for more than 10 years before its eventual discovery in 2009. Further, his thesis describes, in detail, the innovative approach Dr. Gillberg took to this analysis. Through the use of Boosted Decision Trees, a machine-learning technique, he observed the tiny single top signal within an otherwise overwhelming background. This Doctoral Thesis has been accepted by Simon Fraser University, Burnaby, BC, Canada.

Hadron colliders probe physics at new energy frontiers and search for new particles and forces. In addition, hadron colliders now provide also an environment for precision physics. The present volume collects the results from recently completed runs at major colliders as well as new ideas about collider physics and techniques. It will serve as the main source of reference in the field for many years to come.

The proceedings of this series of annual symposia represent an extensive summary of the experimental and theoretical status of high energy physics at hadron colliders. This volume discusses the latest results on top and beauty physics, QCD, electroweak physics and searches for new particles. The prospects of this field for LHC, Tevatron and Hera machines are also reported.

The hunt for top quarks began back in the 1970s after the proposal of the sixquark model by Kobayashi and Maskawa, and it was discovered in 1995 at the Fermilab Tevatron. It was experimentally established by five different experiments in different production modes and a variety of collision energies. At the CERN Large Hadron Collider (LHC), top quark-antiquark pairs are routinely produced at a rate of about six per minute, enabling experiments to make detailed measurements of the properties of top quarks. The analysis of the data collected at the Tevatron and the LHC experiments has revealed, so far, good agreement with the standard model (SM) predictions. The top quark is the most massive elementary particle identified to date: not only does it have a privileged Yukawa coupling to the Higgs boson, but its mass is also significantly higher than that of the Higgs boson. Owing to its large mass, the top quark decays before hadronization, making the study of "bare" quark properties possible in experimental settings. Therefore, top quark physics simultaneously pushes the frontiers of quantum chromodynamics, electroweak, and flavor physics. The aim of this reprint is to provide a comprehensive review of the status and prospects of top quark physics at the LHC and possible future colliders. We have included articles that especially emphasize where the present understanding is incomplete and suggest new directions for research in this area.

The Large Hadron Collider (LHC), located at CERN, Geneva, Switzerland, is the world's largest and highest energy and highest intensity particle accelerator. Here is a timely book with several perspectives on the hoped-for discoveries from the LHC.This book provides an overview on the techniques that will be crucial for finding new physics at the LHC, as well as perspectives on the importance and implications of the discoveries. Among the accomplished contributors to this book are leaders and visionaries in the field of particle physics beyond the Standard Model, including two Nobel Laureates (Steven Weinberg and Frank Wilczek), and presumably some future Nobel Laureates, plus top younger theorists and experimenters. With its blend of popular and technical contents, the book will have wide appeal, not only to physical scientists but also to those in related fields.