At the Leading Edge


Book Description

Too often descriptions of detectors focus on the "what" and not the "why." This volume aims to elucidate how the requirements of the physics at the Large Hadron Collider (LHC) define the detector environment. In turn, the detector choices are made to adopt to that environment. The goal of LHC physics is to explore the mechanism for electroweak symmetry breaking. Because of the minuscule cross-sections which need to be explored, 0.1 fb, the LHC needs to provide 100 fb-1/yr, or an instantaneous luminosity of 1034 / (cm2 sec). With a bunch crossing interval of 25 nsec, well matched to detector speeds, there will be 25 events occupying each bunch crossing. Thus the physics requires fast, finely segmented, low noise and radiation resistant detectors which provide redundant measurements of the rarely produced electrons and muons. To achieve those goals, new ground was broken in constructing the A Toroidal LHC Apparatus (ATLAS) and Compact Muon Solenoid (CMS) detectors in the vertex detectors, tracking systems, calorimetry, strong magnets, muon systems, front end electronics, trigger systems, and in the data acquisition methods used.




At The Leading Edge: The Atlas And Cms Lhc Experiments


Book Description

Too often descriptions of detectors focus on the 'what' and not the 'why'. This volume aims to elucidate how the requirements of the physics at the Large Hadron Collider (LHC) define the detector environment. In turn, the detector choices are made to adopt to that environment. The goal of LHC physics is to explore the mechanism for electroweak symmetry breaking. Because of the minuscule cross-sections which need to be explored, 0.1 fb, the LHC needs to provide 100 fb-1/yr, or an instantaneous luminosity of 1034 / (cm2 sec). With a bunch crossing interval of 25 nsec, well matched to detector speeds, there will be 25 events occupying each bunch crossing.Thus the physics requires fast, finely segmented, low noise and radiation resistant detectors which provide redundant measurements of the rarely produced electrons and muons. To achieve those goals, new ground was broken in constructing the A Toroidal LHC ApparatuS (ATLAS) and Compact Muon Solenoid (CMS) detectors in the vertex detectors, tracking systems, calorimetry, strong magnets, muon systems, front end electronics, trigger systems, and in the data acquisition methods used.




Towards Global Interpretation of LHC Data


Book Description

This book presents the first global interpretation of measurements of jet and top quark production at the Large Hadron Collider, including a simultaneous extraction of the standard model parameters together with constraints on new physics, unbiased from the assumptions on the standard model parameters. As a long-standing problem, any hadron collider search for new physics depends on parton distribution functions, which cannot be predicted but are extracted experimentally. However, performing the extraction in the same kinematic region where physics beyond the standard model is expected to manifest causes the risk of absorbing the new physics effects into the parton distributions. In this book, the issue is addressed by extending the standard model by effective contributions from quark contact interactions describing new physics and extracting the parton distributions and standard model parameters simultaneously with setting limits on the contact interactions. In the process, the most precise single measurement of the strong coupling constant at the LHC is performed, to date. Furthermore, the book details the first investigation of the mass renormalization scale dependence of the top quark mass, highlighting the importance of a proper scale choice for obtaining robust predictions and improving the precision of experimental analyses. The initial chapters provide the reader with a succinct yet accessible introduction to the relevant theoretical and experimental topics. The presented investigations are at the edge of precision in the phenomenology of high-energy physics and serve to pave the road toward a global interpretation of LHC data.




Technology Meets Research - 60 Years Of Cern Technology: Selected Highlights


Book Description

'The contributions from leading scientists of the day collected in this relatively slim book document CERN's 60-year voyage of innovation and discovery, the repercussions of which vindicate the vision of those who drove the foundation of the laboratory — European in constitution, but global in impact. The spirit of inclusive collaboration, which was a key element of the original vision for the laboratory, together with the aim of technical innovation and scientific excellence, are reflected in each of the articles in this unique volume.'CERN Courier'Big' science and advanced technology are known to cross-fertilize. This book emphasizes the interplay between particle physics and technology at CERN that has led to breakthroughs in both research and technology over the laboratory's first 60 years. The innovations, often the work of individuals or by small teams, are illustrated with highlights describing selected technologies from the domains of accelerators and detectors. The book also presents the framework and conditions prevailing at CERN that enabled spectacular advances in technology and contributed to propel the European organization into the league of leading research laboratories in the world.While the book is specifically aimed at providing information for the technically interested general public, more expert readers may also appreciate the broad variety of subjects presented. Ample references are given for those who wish to further explore a given topic.




Photon Physics at the LHC


Book Description

This thesis reports on the first studies of Standard Model photon production at the Large Hadron Collider (LHC) using the ATLAS detector. Standard Model photon production is a large background in the search for Higgs bosons decaying into photon pairs, and is thus critical to understand. The thesis explains the techniques used to reconstruct and identify photon candidates using the ATLAS detector, and describes a measurement of the production cross section for isolated prompt photons. The thesis also describes a search for the Higgs boson in which the analysis techniques used in the measurement are exploited to reduce and estimate non-prompt backgrounds in diphoton events.




Particle Physics Experiments at High Energy Colliders


Book Description

Written by one of the detector developers for the International Linear Collider, this is the first textbook for graduate students dedicated to the complexities and the simplicities of high energy collider detectors. It is intended as a specialized reference for a standard course in particle physics, and as a principal text for a special topics course focused on large collider experiments. Equally useful as a general guide for physicists designing big detectors.




Particle Physics in the LHC Era


Book Description

This work covers the required mathematical and theoretical tools required for understanding the Standard Model of particle physics. It explains the accelerator and detector physics which are needed for the experiments that underpin the Standard Model.




Study of the Inclusive Beauty Production at CMS and Construction and Commissioning of the CMS Pixel Barrel Detector


Book Description

This thesis describes one of the first measurements at the CERN LHC -- the world's largest and highest-energy particle collider. The CMS collision data is analyzed, and results in the first measurement of the inclusive b cross section using semileptonic decays at a center of mass energy of 7 TeV.




Atlas: A 25-year Insider Story Of The Lhc Experiment


Book Description

This book is written by the ATLAS Collaboration at CERN's Large Hadron Collider (LHC), to document and reflect on its more than 25 years of history. It covers all aspects of this global science project at the forefront of particle physics. The historical part recalls first the early stages of discussions in the community leading to the formation of the collaboration in 1992. In a unique approach, the second part documents the evolution from early detector concepts to the final instrument, covering the technical, financial and human aspects. This includes the phases of construction of detector components in the various institutes around the world as well as their installation and commissioning in the underground cavern at CERN.An important part is devoted to the operation of the whole experiment. The book highlights the capabilities and physics accomplishments so far, including the Higgs boson discovery (jointly announced with CMS). It features the various aspects of a broad spectrum of activities needed to arrive at the physics results. The book includes also an outlook to the detector upgrade activities preparing the experiment for the high-luminosity LHC phase of the next decades. Last but not least, it reveals the human aspects of the large ATLAS community working together pursuing common physics goals.The book is aimed at a broad readership with interest in large science projects and their history, as well as in the human endeavour of a worldwide collaboration.




Understanding The Universe: From Quarks To Cosmos (Revised Edition)


Book Description

The Big Bang, the birth of the universe, was a singular event. All of the matter of the universe was concentrated at a single point, with temperatures so high that even the familiar protons and neutrons of atoms did not yet exist, but rather were replaced by a swirling maelstrom of energy, matter and antimatter. Exotic quarks and leptons flickered briefly into existence, before merging back into the energy sea.This book explains the fascinating world of quarks and leptons and the forces that govern their behavior. Told from an experimental physicist's perspective, it forgoes mathematical complexity, using instead particularly accessible figures and apt analogies. In addition to the story of quarks and leptons, which are regarded as well-accepted fact, the author (who is a leading researcher at one of the world's highest energy particle physics laboratories) also discusses mysteries at both the experimental and theoretical frontiers, before tying it all together with the exciting field of cosmology and indeed the birth of the universe itself.The text spans the tiny world of the quark to the depths of the universe with breathtaking clarity. The casual student of science will appreciate the careful distinction between what is known (quarks, leptons and antimatter), what is suspected (Higgs bosons, neutrino oscillations and the reason why the universe has so little antimatter) and what is merely dreamed (supersymmetry, superstrings and extra dimensions). Included is an unprecedented chapter explaining the accelerators and detectors of modern particle physics experiments. The chapter discussing the hunt for the Higgs boson — currently consuming the efforts of nearly 6000 physicists — reveals drama that only big-stakes science can give. Understanding the Universe leaves the reader with a deep appreciation of the fascinating particle realm and reverence for just how much it determines the rich beauty of our universe.Since the release of the first edition, the landscape has changed. The venerable Fermilab Tevatron has ceased operations after a quarter century of extraordinary performance, to be replaced by the CERN Large Hadron Collider, an accelerator with a design energy of seven times greater than the Tevatron and a collision rate of nearly a billion collisions per second. The next few years promise to be very exciting as scientists explore this new realm. This revised edition of Understanding the Universe will leave the reader with a deep appreciation of just why physicists are so excited.