We examine the prospects for discovering and elucidating the weakly-coupled Higgs sector at future collider experiments. The Higgs search consists of three phases: (i) discovery of a Higgs candidate, (ii) verification of the Higgs interpretation of the signal, and (iii) precision measurements of Higgs sector properties. The discovery of one Higgs boson with Standard Model properties is not sufficient to expose the underlying structure of the electroweak symmetry breaking dynamics. It is critical to search for evidence for a non-minimal Higgs sector and/or new physics associated with electroweak symmetry breaking dynamics. An improvement in precision electroweak data at future colliders can play a useful role in confirming the theoretical interpretation of the Higgs search results.

During more than 10 years, from 1989 until 2000, the LEP accelerator and the four LEP experiments, ALEPH, DELPHI, L3 and OPAL, have taken data for a large amount of measurements at the frontier of particle physics. The main outcome is a thorough and successful test of the Standard Model of electroweak interactions. Mass and width of the Z and W bosons were measured precisely, as well as the Z and photon couplings to fermions and the couplings among gauge bosons. The rst part of this work will describe the most important physics results of the LEP experiments. Emphasis is put on the properties of the W boson, which was my main research eld at LEP. Especially the precise determination of its mass and its couplings to the other gauge bosons will be described. Details on physics effects like Colour Reconnection and Bose-Einstein Correlations in W-pair events shall be discussed as well. A conclusive summary of the current electroweak measurements, including low-energy results, as the pillars of possible future ndings will be given. The important contributions from Tevatron, like the measurement of the top quark and W mass, will round up the present day picture of electroweak particle physics. This is an open access book.

Supernovae explosion, combustion of solar hydrogen to form helium, heavy quark decay, or nuclear beta radiation, all weak interaction phenomena, are not unrelated to electromagnetism, but closely linked to it through the Higgs field. This ebook contains a modern introduction to the electroweak unification theory, as part of the so called Standard Model of particle physics. Not only some of the key theoretical ideas are exposed in a precise way, but also the experiments that revealed them. The main highlights of the theory consolidation process are examined which, concerning its experimental counterpart, span over 40 years, from the discovery of neutral currents in1973 to the Higgs boson in 2012. The reader is assumed to have been introduced to Quantum Mechanics and theories based on the gauge invariance principle, and to be familiar with Dirac’s theory for the relativistic electron. The course is specially suited for undergraduate students in physics, as part of an optional subject of elementary particles. The course consists in nine lectures, that on the blackboard take about 90 minutes each. It contains a very select collection of problems and exercises, having as a connecting thread the calculation of the lifetime of elementary fermions and bosons, as well as the comprehension of some experimental results of historical relevance.

High precision measurements of weak neutral current and charged current processes and of the properties of the Z and W bosons have established the standard electroweak model as correct down to a distance scale of 10-16 cm, and are a sensitive probe of possible underlying physics. In this book, all aspects of the program are considered in detail, including the structure of the standard model, radiative corrections, high precision experiments, and their implications. The major classes of experiments are surveyed, covering the experiments themselves, the data analysis, results, and prospects.This volume is a detailed reference for theoretical and experimental researchers, as well as an introductory text for advanced students.

The Standard Model of particle physics is extremely successful in describing nature. It is, however, incomplete in one major way: the masses of gauge bosons and fermions enter the Standard Model through the Higgs mechanism. That is completely satisfactory technically, but it is not understood physically. We do not yet know what nature really does to give mass to particles. Understanding Higgs physics is necessary in order to complete the Standard Model, and to learn how to extend it and improve its foundations.This book is a collection of current work and thinking about these questions by active workers. It speculates about what form the answers will take, as well as updates and extends previous books and reviews. Some chapters emphasize theoretical questions, some focus on connections with other areas of physics, and some discuss how we can get data to uncover nature's solution. This second edition adds information and insights from the last five years, including the recent indirect but statistically significant evidence for the existence of a Higgs boson from precision measurements. It contains contributions from Blondel, Quiros, Haber, Pokorski, Dawson, Janot, Mrenna, Gunion, Ibanez, Ross, Bigi, Carena, Wagner, Georgi, Chanowitz, Yuan, Hill, and others.

This up-to-date volume reviews the recent contributions of electron-positron colliders to the precision test of the electroweak Standard Model. In particular, it contains a short summary of the measurements at the Z resonance and gives an overview of the electroweak processes above the Z. Subsequently, the measurement of the W mass at LEP is discussed in detail. The implications for the precision test of the Standard Model are presented, giving the status of the global electroweak fit before the startup of Large Hadron Collider. The final chapters give an outlook on the electroweak physics at a future linear collider. The book also features many illustrations and tables. Readers obtain a coherent overview of the results of 20 years of electroweak physics conducted at electron-positron colliders.

The masses of fermions and gauge bosons enter the Standard Model through the Higgs mechanism, which is satisfactory technically but is not understood physically. We do not know what nature really does to give mass to particles, nor what experimental clues will lead us to nature's solution. Understanding Higgs physics is necessary in order to complete the Standard Model, and to learn how to extend it and improve its foundations.This book is a collection of current work and thinking about these questions by active workers. It speculates about what form the answers will take, as well as updates and extends previous books and reviews. Some chapters emphasize theoretical questions, some focus on connections with other areas of physics, and some discuss how we can get the data to uncover nature's solution.