This monograph surveys the role of some associative and non-associative algebras, remarkable by their ubiquitous appearance in contemporary theoretical physics, particularly in particle physics. It concerns the interplay between division algebras, specifically quaternions and octonions, between Jordan and related algebras on the one hand, and unified theories of the basic interactions on the other. Selected applications of these algebraic structures are discussed: quaternion analyticity of Yang-Mills instantons, octonionic aspects of exceptional broken gauge, supergravity theories, division algebras in anyonic phenomena and in theories of extended objects in critical dimensions. The topics presented deal primarily with original contributions by the authors.

This thesis presents two production cross-section measurements of pairs of massive bosons using final states with leptons, made with the ATLAS detector at the Large Hadron Collider. The first measurement, performed using data collected in 2012 at center-of-mass energy s = 8 TeV, is the first fiducial and differential cross-section measurement of the production of the Higgs Boson when it decays to four charged leptons (electrons or muons). The second measurement is the first fiducial and inclusive production cross-section measurement of WZ pairs at center-of-mass energy s = 13 TeV using final states with three charged leptons. A significant portion of the thesis focuses on the methods used to identify electrons from massive boson decay-important for many flagship measurements-and on assessing the efficiency of these particle identification techniques. The chapter discussing the WZ pair cross-section measurement provides a detailed example of an estimate of lepton background in the context of an analysis with three leptons in the final state.

The research presented here includes important contributions on the commissioning of the ATLAS experiment and the discovery of the Higgs boson. The thesis describes essential work on the alignment of the inner tracker during the commissioning of the experiment and development of the electron identification algorithm. The subsequent analysis focuses on the search for the Higgs boson in the WW channel, including the development of a method to model the critical W+jet background. In addition, the thesis provides excellent introductions, suitable for non-specialists, to Higgs physics, to the LHC, and to the ATLAS experiment.

The great advantage of coincidence measurements is that by suitable choice of the kinematical and geometrical arrangement one may probe delicate physical effects which would be swamped in less differential experiments. The measurement of the triple dif ferential and higher-order cross sections presents enormous technical difficulties, but refined experiments of this type provide an insight into the subtleties of the scattering process and offer a welcome, if severe, test of the available theoretical models. The last few years have been an exciting time to work in the field and much has been learned. Profound insights have been gleaned into the basic Coulomb few body problem in atomic physics: the experimental study of the fundamental (e,2e) processes on hydrogen and helium targets continues to add to our knowledge and indeed to challenge the best of our theoretical models; significant advances have been made in the understanding of the "double excitation problem," that is the study of ionization processes with two active target electrons: important measurements of (e,3e), (, ), 2e), excitation-ionization and excitation autoionization have been reported and strides have been made in their theoretical description; the longstanding discrepancies between theory and experiment for relativistic (e,2e) processes were resolved, spin dependent effects predicted and ob served and the first successful coincidence experiments on surfaces and thin films were announced. Theory and experiment have advanced in close consort. The papers pre sented here cover the whole gambit of research in the field. Much has been achieved but much remains to be done."

The original work presented in this thesis constitutes an important contribution to modern Cosmic Ray (CR) physics, and comes during one of the most exciting periods of this field. The first part introduces a new numerical code (DRAGON) to model the CR propagation in our Galaxy. The code is then used to perform a combined analysis of CR data, making it possible to determine their propagation properties with unprecedented accuracy. The second part is dedicated to a theoretical interpretation of the recent crucial experimental results on cosmic electron and positron spectra (PAMELA, Fermi-LAT experiments). Using the tools developed in the first part of the thesis, the author convincingly argues for the existence of a new spectral component, which could arise either from local astrophysical sources, such as pulsars, or from Dark Matter annihilation or decay. This thesis is a highly advanced work; the methods, analysis and results are clearly and carefully presented. This work is set to become an important reference document for any future work in this area.

This is a collection of important lecture and original articles and commentaries by Martin Perl, discoverer of the tau lepton and the third generation of elementary particles, and this year's Nobel Prize winner. This book contains a fascinating and realistic picture of experimental science based on the high energy physics research work carried out by him. Using reprints of his articles with his commentaries, the author presents the various aspects of experimental research in science: the pleasures and risks of experimental work; the pain and frustration with experiments that are useless or fail; the dreaming about experiments that were not carried out; the constant search for innovation and creativity in the work; and the special joy of discovery. The articles and commentaries range from the early days of bubble chambers and spark chambers in the 1950's to the author's present research, experiments at an electron-positron collider and a search for free quarks. The book is for the general reader as well as the scientist.

This book reviews recent contributions of electron positron colliders to the precision test of the electroweak Standard Model. It includes a short summary of the measurements at the Z resonance and gives an overview of the electroweak processes above the Z. Subsequently, measurements of the W mass at LEP are discussed in detail. Late chapters offer an outlook on electroweak physics at the future LHC. Also features many illustrations and tables.

In this thesis the author discusses the phenomenology of supersymmetric models by means of experimental data set analysis of the electric dipole moment. There is an evaluation of the elementary processes contributing to the electric dipole moments within R-parity-violating supersymmetry, which call for higher-order perturbative computations.

A new method based on linear programming is developed and for the first time the non-trivial parameter space of R-parity violation respecting the constraints from existing experimental data of the electric dipole moment is revealed. As well, the impressive efficiency of the new method in scanning the parameter space of the R-parity-violating sector is effectively demonstrated. This new method makes it possible to extract from the experimental data a more reliable constraint on the R-parity violation.

This book contains selected papers of Prof Nambu who is one of the most original and outstanding particle theorists of our time. This volume consists of about 40 papers which made fundamental contributions to our understanding of particle physics during the last few decades. The unpublished lecture note on string theory (1969) and the first paper on spontaneous symmetry breaking (1961) are retyped and included. The book also contains a memoir of Prof Nambu on his research career.

This book contains selected papers of Prof Nambu who is one of the most original and outstanding particle theorists of our time. This volume consists of about 40 papers which made fundamental contributions to our understanding of particle physics during the last few decades. The unpublished lecture note on string theory (1969) and the first paper on spontaneous symmetry breaking (1961) are retyped and included. The book also contains a memoir of Prof Nambu on his research career.

Much instrumentation has been developed for imaging the trajectories of elementary particles produced in high energy collisions. Since 1968, gaseous detectors, beginning with multiwire chambers and drift chambers, have been used for the visualisation of particle trajectories and the imaging of X-rays, neutrons, hard gamma rays, beta rays and ultraviolet photons. This book commemorates the groundbreaking research leading to the evolution of such detectors carried out at CERN by Georges Charpak, Nobel Prizewinner for Physics in 1992. Besides collecting his key papers, the book also includes original linking commentary which sets his work in the context of other worldwide research.

Much instrumentation has been developed for imaging the trajectories of elementary particles produced in high energy collisions. Since 1968, gaseous detectors, beginning with multiwire chambers and drift chambers, have been used for the visualisation of particle trajectories and the imaging of X-rays, neutrons, hard gamma rays, beta rays and ultraviolet photons. This book commemorates the groundbreaking research leading to the evolution of such detectors carried out at CERN by Georges Charpak, Nobel Prizewinner for Physics in 1992. Besides collecting his key papers, the book also includes original linking commentary which sets his work in the context of other worldwide research.

Scattering of light by light is a fundamental process arising at the quantum level through vacuum fluctuations. This short book will explain how, remarkably enough, this quantum process can entirely be described in terms classical quantities. This description is derived from general principles, such as causality, unitarity, Lorentz, and gauge symmetries. The reader will be introduced into a rigorous formulation of these fundamental concepts, as well as their physical interpretation and applications.

This book provides a novel introduction to the Standard Model of electroweak unification. It presents, in pedagogical form, a detailed derivation of the Standard Model from the high energy behavior of tree-level Feynman graphs. In this respect, the present text is unique among the existing monographs and textbooks on this subject, and fills a gap in the current literature on electroweak interactions.

th This workshop was the 15 in a series that addresses the subject of the dynamics of nuclear reactions. These workshops are dedicated to the concept that bringing together scientists from diverse areas of nuclear reactions promotes the vibrant exchange of ideas. This workshop hosted presentations from experimentalists and theorists, intermediate energy to ultrarelativistic energies, and final results to recent speculations. Many of these scientists would not normally be exposed to the work done in other subfields. Thus the Winter Workshop on Nuclear Dynamics plays a unique role in information exchange and the stimulation of new ides. The field of nuclear dynamics has a bright future. New accelerators are being planned and completed around the world. New detectors are being constructed. New models and theories are being developed to describe these phenomena. The Winter Workshop on Nuclear Dynamics will continue to promote this lively and compelling field of research. WOLFGANG BAUER AND GARY D. WESTFALL v Previous Workshops The following table contains a list of the dates and locations of the previous Winter Workshops on Nuclear Dynamics as well as the members of the organizing committees. The chairpersons of the conferences are underlined.

This thesis covers the few-cycle laser-driven acceleration of electrons in a laser-generated plasma. This process, known as laser wakefield acceleration (LWFA), relies on strongly driven plasma waves for the generation of accelerating gradients in the vicinity of several 100 GV/m, a value four orders of magnitude larger than that attainable by conventional accelerators. This thesis demonstrates that laser pulses with an ultrashort duration of 8 fs and a peak power of 6 TW allow the production of electron energies up to 50 MeV via LWFA. The special properties of laser accelerated electron pulses, namely the ultrashort pulse duration, the high brilliance, and the high charge density, open up new possibilities in many applications of these electron beams.

The Salamfest was held to honor Prof Abdus Salam whose scientific contribution to the development and dissemination of physics has deeply influenced the course of scientific advancement. Colleagues, collaborators and former students met together to celebrate his scientific achievements, and discuss the highlights of recent advances in experiment and phenomenology in particle and condensed matter physics.The Contributors are: A Ali, G Altarelli, L Alvarez-Gaume, D Amati, J Bahcall, A Chamseddine, R Delbourgo, M Duff, J Ellis, J Feltesse, P Frampton, M Green, G 't Hooft, T Kibble, G Mack, Y Ne'eman, L O'Raifeartaigh, J Pati, R Peccei, S Randjbar-Daemi, Riazuddin & Fayyazuddin, D Schramm, H Schroeder, D Sciama, E Sezgin, Q Shafi, C Vafa, S Weinberg, P West, B Winstein, E Witten, C N Yang, A Zichichi and B Zumino.

This book explores the relaxation dynamics of inner-valence-ionized diatomic molecules on the basis of extreme-ultraviolet pump-probe experiments performed at the free-electron laser (FEL) in Hamburg. Firstly, the electron rearrangement dynamics in dissociating multiply charged iodine molecules is studied in an experiment that made it possible to access charge transfer in a thus far unexplored quasimolecular regime relevant for plasma and chemistry applications of the FEL. Secondly the lifetime of an efficient non-radiative relaxation process that occurs in weakly bound systems is measured directly for the first time in a neon dimer (Ne2). Interatomic Coulombic decay (ICD) has been identified as the dominant decay mechanism in inner-valence-ionized or excited van-der-Waals and hydrogen bonded systems, the latter being ubiquitous in all biomolecules. The role of ICD in DNA damage thus demands further investigation, e.g. with regard to applications like radiation therapy.

This book is a useful and accessible introduction to symmetry principles in particle physics. New ideas are explained in a way that throws considerable light on difficult concepts, such as Lie groups and their representations. This book begins with introdutions both to the types of symmetries known in physics and to group theory and representation theory. Successive chapters deal with the symmetric groups and their Young diagrams, braid groups, Lie groups and algebras, Cartan's classification of semi-simple groups, and the Lie groups most used in physics are treated in detail. Gauge groups are discussed, and applications to elementary particle physics and multiquark systems introduced throughout the book where appropriate. Many worked examples are also included. There is a growing interestinthe quatk structure of hadrons and in theories of particle interactions based on the principle of gauge symmetries. In this book the concepts of group theory are clearly explained and their applications to subnuclear physics brought up-to-date.

The physics of highly charged ions continues to be one of the most active and interesting fields of atomic physics. A large fraction of the characteristic radiation of such ions lies in the x-ray region and its spectroscopy represents an important experimental tool. The field of x-ray spectroscopy grew directly from the discovery of x radiation by Wilhelm Conrad Rontgen in 1895. The early contributions to atomic physics that arose out of x-ray spectroscopy are well documented and are the subject of many centennial events. In the past, the gross features of most x-ray spectra in the hard x-ray region have been accounted for on a hydrogenic model. In many instances the gross spectral features recorded in the early days of x-ray physics match those observed with state-of-the-art techniques today and many of the early qualitative - terpretations have remained unchanged. It is in the details of the spectra that today's results are superior to those obtained many years ago, and it is in the quantitative and accurate - scriptions that today's predictions are better. A rejuvenation of the field has occurred after the great achievements in the development of new ion sources for production of heavy ions with only one or few electrons. The new tools available to the experimenter allow the exploration of new states of m- ter and allow us to challenge new frontiers in our theoretical understanding of atoms and their interactions with other particles.

Gauge theory, which underlies modern particle physics as well as the theory of gravity, and hence all of physics as we know it today, is itself based on a few fundamental concepts, the consequences of which are often as beautiful as they are deep. Unfortunately, in view of the pressure to cover aspects of the theory that are necessary for its many important applications, very little space is usually devoted in textbooks and graduate courses to the treatment of these concepts. The present small volume is an attempt to help in some degree to redress this imbalance in the literature.The topics covered are elementary in the sense of being basic, not in the sense of being shallow or easy. Although all will already feature at the classical field level, and most even before the introduction of an action principle, they often lead one to pose some quite profound questions, so that much of the material treated is by necessity at the front line of research. The approach adopted is physically motivated, although there is no hesitation in introducing mathematical concepts when they are a help to understanding. In the presentation, little is assumed of the reader, and no pains has been spared to make the whole volume understandable to researchers in other fields and to graduate students, provided that the reader is willing to devote sufficient effort required by the subject matter. On the other hand, neither has there been any conscious attempt to avoid essential difficulties, or to trivialise concepts which are intrinsically abstruse. It is thus hoped that the result will be enjoyable reading for researchers and students alike.

Gamma-ray astronomy began in the mid-1960s with balloon satellite, and, at very high photon energies, also with ground-based instruments. However, the most significant progress was made in the last decade of the 20th century, when the tree satellite missions SIGMA, Compton, and Beppo-Sax gave a completely new picture of our Universe and made gamma-ray astronomy an integral part of astronomical research. This book, written by well-known experts, gives the first comprehensive presentation of this field of research, addressing both graduate students and researchers. Gamma-ray astronomy helps us to understand the most energetic processes and the most violent events in the Universe. After describing cosmic gamma-ray production and absorption, the instrumentation used in gamma-ray astronomy is explained. The main part of the book deals with astronomical results, including the somewhat surprising result that the gamma-ray sky is continuously changing.

This collection of lectures and essays by eminent researchers in the field, many of them nobel laureates, is an outgrow of a special event held at CERN in late 2009, coinciding with the start of LHC operations. Careful transcriptions of the lectures have been worked out, subsequently validated and edited by the lecturers themselves. This unique insight into the history of the field includes also some perspectives on modern developments and will benefit everyone working in the field, as well as historians of science.

Gauge theory, which underlies modern particle physics as well as the theory of gravity, and hence all of physics as we know it today, is itself based on a few fundamental concepts, the consequences of which are often as beautiful as they are deep. Unfortunately, in view of the pressure to cover aspects of the theory that are necessary for its many important applications, very little space is usually devoted in textbooks and graduate courses to the treatment of these concepts. The present small volume is an attempt to help in some degree to redress this imbalance in the literature.The topics covered are elementary in the sense of being basic, not in the sense of being shallow or easy. Although all will already feature at the classical field level, and most even before the introduction of an action principle, they often lead one to pose some quite profound questions, so that much of the material treated is by necessity at the front line of research. The approach adopted is physically motivated, although there is no hesitation in introducing mathematical concepts when they are a help to understanding. In the presentation, little is assumed of the reader, and no pains has been spared to make the whole volume understandable to researchers in other fields and to graduate students, provided that the reader is willing to devote sufficient effort required by the subject matter. On the other hand, neither has there been any conscious attempt to avoid essential difficulties, or to trivialise concepts which are intrinsically abstruse. It is thus hoped that the result will be enjoyable reading for researchers and students alike.

For scientific, technological and organizational reasons, the end of World War II (in 1945) saw a rapid acceleration in the tempo of discovery and understanding in nuclear physics, cosmic rays and quantum field theory, which together triggered the birth of modern particle physics. The first fifteen years (1945-60) following the war's end - the "Startup Period" in modern particle physics -witnessed a series of major experimental and theoretical developments that began to define the conceptual contours (non-Abelian internal symmetries, Yang-Mills fields, renormalization group, chirality invariance, baryon-lepton symmetry in weak interactions, spontaneous symmetry breaking) of the quantum field theory of three of the basic interactions in nature (electromagnetic, strong and weak). But it took another fifteen years (1960-75) - the "Heroic Period" in modern particle physics - to unravel the physical content and complete the mathematical formulation of the standard gauge theory of the strong and electroweak interactions among the three generations of quarks and leptons. The impressive accomplishments during the "Heroic Period" were followed by what is called the "period of consolidation and speculation (1975-1990)", which includes the experimental consolidation of the standard model (SM) through precision tests, theoretical consolidation of SM through the search for more rigorous mathematical solutions to the Yang-Mills-Higgs equations, and speculative theoretical excursions "beyond SM".Within this historical-conceptual framework, the author - himself a practicing particle theorist for the past fifty years - attempts to trace the highlights in the conceptual evolution of modern particle physics from its early beginnings until the present time. Apart from the first chapter - which sketches a broad overview of the entire field - the remaining nine chapters of the book offer detailed discussions of the major concepts and principles that prevailed and were given wide currency during each of the fifteen-year periods that comprise the history of modern particle physics. Those concepts and principles that contributed only peripherally to the standard model are given less coverage but an attempt is made to inform the reader about such contributions (which may turn out to be significant at a future time) and to suggest references that supply more information. Chapters 2 and 3 of the book cover a range of topics that received dedicated attention during the "Startup Period" although some of the results were not incorporated into the structure of the standard model. Chapters 4-6 constitute the core of the book and try to recapture much of the conceptual excitement of the "Heroic Period", when quantum flavordynamics (QFD) and quantum chromodynamics (QCD) received their definitive formulation. [It should be emphasized that, throughout the book, logical coherence takes precedence over historical chronology (e.g. some of the precision tests of QFD are discussed in Chapter 6)]. Chapter 7 provides a fairly complete discussion of the chiral gauge anomalies in four dimensions with special application to the standard model (although the larger unification models are also considered). The remaining three chapters of the book (Chapters 7-10) cover concepts and principles that originated primarily during the "Period of Consolidation and Speculation" but, again, this is not a literal statement. Chapters 8 and 9 report on two of the main directions that were pursued to overcome acknowledged deficiencies of the standard model: unification models in Chapter 8 and attempts to account for the existence of precisely three generations of quarks and leptons, primarily by means of preon models, in Chapter 9. The most innovative of the final three chapters of the book is Chapter 10 on topological conservation laws. This last chapter tries to explain the significance of topologically non-trivial solutions in four-dimensional (space-time) particle physics (e.g. 't Hooft-Polyakov monopoles, instantons, sphalerons, global SU(2) anomaly, Wess-Zumino term, etc.) and to reflect on some of the problems that have ensued (e.g. the "strong CP problem" in QCD) from this effort. It turns out that the more felicitous topological applications of field theory are found - as of now - in condensed matter physics; these successful physical applications (to polyacetylene, quantized magnetic flux in type-II low temperature superconductivity, etc.) are discussed in Chapter 10, as a good illustration of the conceptual unity of modern physics.