Partikelfysik og højenergifysik

This thesis describes two groundbreaking measurements in the precision frontier at the LHC: the first ever differential measurement of the Z-associated single top quark (tZq) production, and the luminosity measurement using Z boson production rate for the first time in CMS. Observed only in 2018, the tZq process is of great importance in probing top quark electroweak couplings. These couplings are natural places for new phenomena to happen in the top quark sector of the standard model. Yet, they are the least explored directly. One has to obtain a firm understanding of the modeling of sensitive distributions to new top-Z interactions. The present analysis marks a major milestone in this long-term effort. All distributions relevant for new phenomena, and/or modeling of tZq, are studied in full depth using advanced Machine Learning techniques.The luminosity and its uncertainty contributes to every physics result of the experiment. The method minutely developed in this thesis provides a complementary measurement that results in a significant overall reduction of uncertainties.

This book provides an advanced introduction to extended theories of quantum field theory and algebraic topology, including Hamiltonian quantization associated with some geometrical constraints, symplectic embedding and Hamilton-Jacobi quantization and Becchi-Rouet-Stora-Tyutin (BRST) symmetry, as well as de Rham cohomology. This extended new edition offers a multifaced insight into phenomenology of particles such as baryons and photons, in terms of extended objects. In particular, in the second edition, the baryons are described in hypersphere soliton model, and the photon properties are additionally included in stringy photon model and in Dirac type relativistic quantum mechanics for a photon.It offers a critical overview of the research in this area and unifies the existing literatures, employing a consistent notation. Although the results presented apply in principle to all alternative quantization schemes, special emphasis is placed on the BRST quantization and its de Rham cohomology group which contribute to a deep understanding of constrained physical theories. The book describes how solitons and other models subject to constraints include rigorous treatments of the geometrical constraints which affect the predictions themselves. The book is intended for use by any graduate-level student with quantum field and relativity theories, and it also serves as a useful reference for those working in the field. An extensive bibliography guides the reader toward the source literature on particular topics.

The Standard Model is the most comprehensive physical theory ever developed. This textbook conveys the basic elements of the Standard Model using elementary concepts, without the theoretical rigor found in most other texts on this subject. It contains examples of basic experiments, allowing readers to see how measurements and theory interplay in the development of physics. The author examines leptons, hadrons and quarks, before presenting the dynamics and the surprising properties of the charges of the different forces. The textbook concludes with a brief discussion on the discoveries of physics beyond the Standard Model, and its connections with cosmology. Quantitative examples are given, and the reader is guided through the necessary calculations. Each chapter ends in the exercises, and solutions to some problems are included in the book. Complete solutions are available to instructors at www.cambridge.org/9781107406094.

This open access book bridges a gap between introductory Quantum Field Theory (QFT) courses and state-of-the-art research in scattering amplitudes. It covers the path from basic definitions of QFT to amplitudes, which are relevant for processes in the Standard Model of particle physics. The book begins with a concise yet self-contained introduction to QFT, including perturbative quantum gravity. It then presents modern methods for calculating scattering amplitudes, focusing on tree-level amplitudes, loop-level integrands and loop integration techniques. These methods help to reveal intriguing relations between gauge and gravity amplitudes and are of increasing importance for obtaining high-precision predictions for collider experiments, such as those at the Large Hadron Collider, as well as for foundational mathematical physics studies in QFT, including recent applications to gravitational wave physics.These course-tested lecture notes include numerous exercises with solutions. Requiring only minimal knowledge of QFT, they are well-suited for MSc and PhD students as a preparation for research projects in theoretical particle physics. They can be used as a one-semester graduate level course, or as a self-study guide for researchers interested in fundamental aspects of quantum field theory.

This book celebrates the life and work of the late Giovanni Morchio (1944¿2021). It features scientific and anecdotal contributions written by his former colleagues, co-authors, and students, as well as senior scientists who were active witnesses to the dramatic advances in physics and in mathematics that took place during his 50-year-long career. The volume begins with a biographical introduction, detailing Giovanni Morchiös life and his role as a physicist, mathematician, teacher, and scientist. The core of the book covers a vast spectrum of ideas, reflecting Dr Morchiös scientific interests. Each chapter develops a specific topic of modern research, ranging from quantum mechanics and quantum field theory to additional themes such as the connection between general relativity and Newtonian gravitation. Every contribution provides a historical retrospective, a survey of advances, an outlook of future perspectives and challenges, and an updated bibliography. The last part collects the authors¿ recollections of their professional and personal interactions with Dr Morchio, in recognition of his deep achievements, his exceptional pedagogical qualities, and his praiseworthy social and pro bono commitment. Authored by physicists of international calibre covering a broad range of subjects, the book will be a valuable reference for researchers and students of theoretical and mathematical physics.

This thesis presents significant new observations of nuclear wobbling, and thus expands our understanding of nuclear triaxiality and its prevalence in the nuclear chart. Triaxial nuclear shapes are a very rare phenomena and their experimental identification often relies on two unique signatures - nuclear wobbling motion and chiral rotation. While nuclear chirality is a well-studied phenomenon, experimental observations of wobbling nuclei are rather limited. With the identification of 135Pr and 187Au as wobblers, this work establishes triaxiality to be a general phenomenon present in different regions of the nuclear chart, irrespective of any particular spin or deformation. A major focus of this work is the detailed investigation of the different kinds of wobbling modes. Depending on the geometry of the nuclear system, wobbling can be classified into two types - longitudinal and transverse. This work has, for the first time, reported evidence of the possible coexistence of both forms of wobbling in a single nucleus. Another important result reported in this work is the very first observation of co-existing chiral and wobbling modes in the 135Pr nucleus. This thesis details the experimental methods that led to this breakthrough, along with pertinent theoretical interpretations.

The current Standard Model of elementary particles leaves many questions unanswered. For example, it does not provide a quantum mechanical explanation of the mass distribution of elementary particles in the universe. Why are we still not able to prove the existence of gravitons? Is there a connection between elementary particles and dark matter and dark energy? Do we have to include the time axis? The gravitation? So many questions!The answer to all of these questions could be the existence of a new particle, the master particle, which moves faster than the speed of light on the time axis ¿ and is beyond our reach. Through this, a new parallel reality is created, without reference to the world we perceive as real and with a completely different idea of stable states. Two different worlds, one confined by the speed of light, the other surpassing it. This master particle might be part of the elementary particles we know today and would therefore lead to a new model. Essentially, it created the assumption that our physical constants, especially the speed of light, might not be constants at all but change with the increasing age of our universe.

This textbook gradually introduces the reader to several topics related to black hole physics with a didactic approach. It starts with the most basic black hole solution, the Schwarzschild metric, and discusses the basic classical properties of black hole solutions as seen by different probes. Then it reviews various theorems about black hole properties as solutions to Einstein gravity coupled to matter fields, conserved charges associated with black holes, and laws of black hole thermodynamics. Next, it elucidates semiclassical and quantum aspects of black holes, which are relevant in ongoing and future research. The book is enriched with many exercises and solutions to assist in the learning.The textbook is designed for physics graduate students who want to start their research career in the field of black holes; postdocs who recently changed their research focus towards black holes and want to get up-to-date on recent and current research topics; advanced researchers intending to teach (or learn) basic and advanced aspects of black hole physics and the associated mathematical tools. Besides general relativity, the reader needs to be familiar with standard undergraduate physics, like thermodynamics, quantum mechanics, and statistical mechanics. Moreover, familiarity with basic quantum field theory in Minkowski space is assumed. The book covers the rest of the needed background material in the main text or the appendices.

This book starts with the mathematical basis of the theory - i.e. provide a brief sketch of the theory of manifolds and frame bundles, tensors and their transformations, relativistic kinematics, and aspects of non-flat space-time geometries. The definition of relevant physical quantities (torsion, curvature, non-metricity, tetrads, connection fields etc.) and important geometry concepts are also included. The main body of the book is devoted to a detailed derivation of the gauge theory of gravitation for scalar, vector (Proca and Maxwell) and Dirac spinor fields. Alternative approaches based on the Noether theorem and on the spinorial representation of the fields are also addressed, as well as important novel features related to the CCGG framework (Birkhoff theorem, field derivative identities etc.). In the last section of the volume the application of the CCGG theory to cosmology will be set out, resulting in a new understanding of dark energy and inflation.

The Standard Model of elementary particle physics was tentatively outlined in the early 1970s. The concepts of quarks, leptons, neutrinos, gauge symmetries, chiral interactions, Higgs boson, strong force, weak force, and electromagnetism were all put together to form a unifying theory of elementary particles. Furthermore, the model was developed within the context of relativistic quantum field theory, making it compatible with all of the laws of Einstein's Special Relativity. The successes of the Standard Model over the years have been tremendous and enduring, leading up to the recent discovery and continuing study of the Higgs boson.      This book is a comprehensive and technical introduction to Standard Model physics. Martin and Wells provide readers who have no prior knowledge of quantum field theory or particle physics a firm foundation into the fundamentals of both. The emphasis is on obtaining practical knowledge of how to calculate cross-sections and decay rates. There is no better way to understand the necessary abstract knowledge and solidify its meaning than to learn how to apply it to the computation of observables that can be measured in a laboratory.Beginning graduate students, both experimental and theoretical, and advanced undergraduate students interested in particle physics, will find this to be an ideal one-semester textbook to begin their technical learning of elementary particle physics.

This thesis addresses the feasibility of the production of ultra-high-energy cosmic rays in starburst galaxies and active galactic nuclei. These astrophysical objects were theoretically proposed as candidate sources a long time ago. Nevertheless, the interest in them has been recently renewed due to the observational data collected by the Pierre Auger Observatory and the Telescope Array. In this work, a comprehensive review of the current status of the research on cosmic rays accelerators is provided, along with a summary of the principal concepts needed to connect these relativistic particles with electromagnetic and neutrino observations in the multi-messenger era. On one hand, the hypothesis of accelerating particles with energies above 10' eV in starburst superwinds is carefully revisited, taking into account the constraints imposed by the most recent electromagnetic observations. On the other hand, an alternative new model for the gamma emission of the nearby active galaxy NGC 1068 is presented. The implications of the results of these studies are discussed in terms of the contemporary observatories and prospects for future experiments are offered.

In addition to expanding and clarifying a number of sections of the first edition, it generalizes the analysis that eliminates the noncausal pre-acceleration so that it applies to removing any pre-deceleration as well. It also introduces a robust power series solution to the equation of motion that produces an extremely accurate solution to problems such as the motion of electrons in uniform magnetic fields.

This book addresses the pursuit and further investigation of experimental results by analyzing classic examples from physics. The authors concentrate on the investigation of experimental results by examining case studies from the history of 20th and 21st century physics. Discussions on the discovery of parity nonconservation, the rise and fall of the Fifth Force, the search for neutrinoless double decay, supersymmetry and the expansion of the Standard Model, and measurements of the anomalous magnetic moment of the muons are provided. Experimental results may achieve acceptance to the point that even well known principles, such as conservation of energy and quantization, lose their status as accepted. Such principles and their options are treated on an equal footing as being pursuit worthy even though there is no plausible explanation as to why and how they might have failed.

This book tells the story of a unique scientific and human adventure, following the life and science of Bruno Touschek, an Austrian born physicist, who conceived and built AdA, the first matter-antimatter colliding-beam storage ring, the ancestor of the Large Hadron Collider at CERN where the Higgs Boson was discovered in 2012. Making extensive use of archival sources and personal correspondence, the author offers for the first time a unified history of European efforts to build modern-day particle accelerators,  from the dark times of war-ravaged Europe up to the rebuilding of science in Germany, UK, Italy and France through the 1950s and early 1960s. This book, the result of several years of scholarly research work, includes numerous previously unpublished photos as well as original drawings by Bruno Touschek. 

If existing models of the structure of the universe are correct, then 85 percent of the cosmos comprises a substance called dark matter. Yet no direct evidence of dark matter exists. Award-winning science journalist Govert Schilling details the quest to detect dark matter and how the search has helped us to understand the universe we inhabit.

2d atoms. Nuclear shapes and nuclear structureThe paper compares the scientific ideas of spherical and deformed atomic nuclei with the previously unknown theory of checkerboard and planar atomic structure. For this purpose, the interpretations of the nuclear structure of international researchers were compared with the author's interpretations according to the checkerboard and planar atomic structure. Helmut Albert, Freiburg / Germany 2023.

This book covers the most common neutron detectors used in neutron scattering facilities and all of those in use at Oak Ridge National Lab. It starts describing the facilities, instruments and the critical detector parameters needed by various instruments. Then the key components of the 3He-based linear position-sensitive detectors as well as on their electronics, which require particular attention to signal processing and noise reduction, are introduced. One chapter is dedicated to the 3He alternatives where scintillators play a critical role. It also covers emerging neutron detection technologies including semiconductors, vacuum-based devices and their associated readouts, which will be required in the future for high rate and high-resolution neutron detectors.The authors explain the logic behind the choice of materials as well as the various constraints that neutron detectors must respect to be useful. Some of these constraints, such as efficiency and gamma-ray sensitivity are common to all neutron counters while others, like timing resolution, dynamic range, and peak counting rate, depend on the applications.The book guides experts, the nuclear science community, and young scholars through the physical processes and the required electronics in a way that is accessible for those not professionally involved in designing detector¿s components and electronic circuits.