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This comprehensive introduction to high transverse momentum reactions at hadron colliders begins with the Standard Model of high energy physics and a description of the specialized detectors used. It then analyzes the reactions and summarizes the state of the art in hadron collider physics defined by Tevatron results. The experimental program at the detectors being built for the Large Hadron Collider at CERN is also described, with details of the general strategy to find the postulated Higgs particle.
Hadron colliders. --- Proton-antiproton interactions. --- Proton-proton interactions.
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Cosmic rays --- Gamma rays --- Particles (Nuclear physics) --- Proton-proton interactions --- Relativistic kinematics
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This thesis describes in detail the search for new phenomena in mono-jet final states with the ATLAS experiment at the LHC. The final state is considered the golden channel in the searches for large extra dimensions (LED) but also allows access to a very rich SUSY-related phenomenology pertaining to the production of weakly interacting massive particles (WIMPS), SUSY Dark Matter candidates, GMSB SUSY models with very light gravitino masses, as well as stop an sbottom pair production in compressed scenarios (with nearly degenerated squarks and the lightest neutralino), and also invisible Higgs searches, among others. Here, a number of these scenarios are explored. The measurements presented yield new powerful constraints on the existence of extra spatial dimensions, the pair production of WIMPs, and also provide the best limit to date on the gravitino mass. .
Nuclear Physics --- Atomic Physics --- Physics --- Physical Sciences & Mathematics --- Proton-proton interactions. --- Jets (Nuclear physics) --- Collisions, Proton --- Interactions, Proton-proton --- Proton interactions --- Proton-proton collisions --- Nuclear reactions --- Scattering (Physics) --- Quantum theory. --- Elementary Particles, Quantum Field Theory. --- Quantum Field Theories, String Theory. --- Quantum dynamics --- Quantum mechanics --- Quantum physics --- Mechanics --- Thermodynamics --- Elementary particles (Physics). --- Quantum field theory. --- String theory. --- Models, String --- String theory --- Relativistic quantum field theory --- Field theory (Physics) --- Quantum theory --- Relativity (Physics) --- Elementary particles (Physics) --- High energy physics --- Nuclear particles --- Nucleons --- Nuclear physics
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This book presents two analyses, the first of which involves the search for a new heavy charged gauge boson, a so-called W¢ boson. This new gauge boson is predicted by some theories extending the Standard Model gauge group to solve some of its conceptual problems. Decays of the W¢ boson in final states with a lepton (ℓ± = e±, µ±) and the corresponding (anti-)neutrino are considered. Data collected by the ATLAS experiment in 2015 at a center of mass energy of sqrt{s}=13 TeV is used for the analysis. In turn, the second analysis presents a measurement of the double-differential cross section of the process pp->Z/gamma^* + X -> l^+l^- + X, including a gamma gamma induced contribution, at a center of mass energy of sqrt{s} = 8 TeV. The measurement is performed in an invariant mass region of 116 GeV to 1500 GeV as a function of invariant mass and absolute rapidity of the l^+l^-- pair, and as a function of invariant mass and pseudorapidity separation of the l^+l^-- pair. The data analyzed was recorded by the ATLAS experiment in 2012 and corresponds to an integrated luminosity of 20.3/fb. It is expected that the measured cross sections are sensitive to the PDFs at very high values of the Bjorken-x scaling variable, and to the photon structure of the proton.
Heavy ions. --- Proton-proton interactions. --- Collisions, Proton --- Interactions, Proton-proton --- Proton interactions --- Proton-proton collisions --- Nuclear reactions --- Ions --- Quantum theory. --- Elementary Particles, Quantum Field Theory. --- Quantum Field Theories, String Theory. --- Quantum dynamics --- Quantum mechanics --- Quantum physics --- Physics --- Mechanics --- Thermodynamics --- Elementary particles (Physics). --- Quantum field theory. --- String theory. --- Models, String --- String theory --- Relativistic quantum field theory --- Field theory (Physics) --- Quantum theory --- Relativity (Physics) --- Elementary particles (Physics) --- High energy physics --- Nuclear particles --- Nucleons --- Nuclear physics
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A measurement of the double differential cross section for inclusive b jet production in proton-proton collisions as well as fraction of b jets in the inclusive jet production is presented as a function of the transverse momentum p T and the absolute rapidity |y|. The data samples were collected in the CMS experiment at LHC during 2016 and correspond to an integrated luminosity of 35.2 fb −1 at a centre-of-mass energy of 13 TeV. The jets are selected with p T > 74 GeV and |y| < 2.4; the b jets must contain a B hadron. The measurement has significant statistics up to p T ∼ O(TeV). Advanced methods of unfolding are performed to extract the signal. It is found that fixed-order calculations with underlying event describe the measurement well.
Proton-proton interactions. --- Collisions, Proton --- Interactions, Proton-proton --- Proton interactions --- Proton-proton collisions --- Nuclear reactions --- Elementary particles (Physics). --- Quantum field theory. --- Mathematical physics. --- Sociophysics. --- Econophysics. --- Elementary Particles, Quantum Field Theory. --- Theoretical, Mathematical and Computational Physics. --- Data-driven Science, Modeling and Theory Building. --- Economics --- Statistical physics --- Mathematical sociology --- Physical mathematics --- Physics --- Relativistic quantum field theory --- Field theory (Physics) --- Quantum theory --- Relativity (Physics) --- Elementary particles (Physics) --- High energy physics --- Nuclear particles --- Nucleons --- Nuclear physics --- Statistical methods --- Mathematics
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This thesis addresses, in a novel and elegant way, a combination of measurements that are used to extract so-called double parton scattering. The method is easy to apply and overcomes many of the technical difficulties of older methods. Many new phenomena in particle physics can be observed when particles are collided at the highest energies; one of the highlights in recent years was the discovery of the Higgs boson at the Large Hadron Collider at CERN. Understanding the production mechanism of the Higgs boson at the LHC requires detailed knowledge of the physics of proton-proton collisions. When the density of partons in the protons becomes large, there is a non-negligible probability that more than one parton participates in the interaction and the so-called double parton scattering becomes important. In some cases very particular final state signatures can be observed, which can be regarded as an indication of such double partonic scattering and where the different interactions can be separated. Such multiple partonic interactions play an important role when precise predictions from known processes are required.
Atomic Physics --- Nuclear Physics --- Physics --- Physical Sciences & Mathematics --- Protons --- Proton-proton interactions. --- Partons. --- Scattering --- Measurement. --- Parton model --- Collisions, Proton --- Interactions, Proton-proton --- Proton interactions --- Proton-proton collisions --- Hydrogen nucleus --- Hadrons --- Particles (Nuclear physics) --- Quarks --- Nuclear reactions --- Atoms --- Baryons --- Matter --- Constitution --- Quantum theory. --- Elementary Particles, Quantum Field Theory. --- Measurement Science and Instrumentation. --- Quantum Field Theories, String Theory. --- Elementary particles (Physics). --- Quantum field theory. --- Physical measurements. --- Measurement . --- String theory. --- Models, String --- String theory --- Measuring --- Mensuration --- Mathematics --- Technology --- Metrology --- Physical measurements --- Measurements, Physical --- Mathematical physics --- Measurement --- Relativistic quantum field theory --- Field theory (Physics) --- Quantum theory --- Relativity (Physics) --- Elementary particles (Physics) --- High energy physics --- Nuclear particles --- Nucleons --- Nuclear physics
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In this book, the anomaly mediated supersymmetry breaking (AMSB) model is explored by searching for charged winos with their subsequent decays collected with the ATLAS detector at the Large Hadron Collider (LHC). The author develops a new method, called “re-tracking,” to detect charged winos that decay before reaching the Semiconductor Tracker (SCT) detector. Because the nominal tracking algorithm at the ATLAS experiment requires at least seven successive hits in the inner tracking system, the sensitivity to charged winos having a fraction of a nanosecond in the past analysis was therefore limited. However, re-tracking requires a minimum of three pixel hits and provides a fully efficient tracking capability for charged winos traversing the pixel detector, resulting in around about 100 times greater efficiency for charged winos with a lifetime ~0.2 ns longer than that in past searches. Signal topology is characterized by a jet with large transverse momentum (pT), large missing transverse energy, and a high-pT disappearing track. There are three types of background tracks: interacting hadron trac ks, charged leptons, and tracks with mismeasured pT. A background estimation based on the Monte Carlo (MC) simulation suffers from large uncertainties due to poor statistics and has difficulty simulating the properties of background tracks. Therefore, a data-driven approach has been developed by the author of the book to estimate the background track-pT spectrum. No significant excess above the background expectation is observed for candidate tracks with large transverse momentum, and constraints on the AMSB model are obtained. The author shows that in the AMSB model, a charged wino mass below 270 GeV is excluded at 95 % confidence level, which also directly constrains the mass of wino dark matter.
Atomic Physics --- Nuclear Physics --- Physics --- Physical Sciences & Mathematics --- Proton-proton interactions. --- Particles (Nuclear physics) --- Elementary particles (Physics) --- High energy physics --- Nuclear particles --- Nucleons --- Collisions, Proton --- Interactions, Proton-proton --- Proton interactions --- Proton-proton collisions --- Nuclear physics --- Nuclear reactions --- Quantum theory. --- Particle acceleration. --- Elementary Particles, Quantum Field Theory. --- Measurement Science and Instrumentation. --- Theoretical, Mathematical and Computational Physics. --- Particle Acceleration and Detection, Beam Physics. --- Acceleration (Mechanics) --- Quantum dynamics --- Quantum mechanics --- Quantum physics --- Mechanics --- Thermodynamics --- Acceleration --- Elementary particles (Physics). --- Quantum field theory. --- Physical measurements. --- Measurement . --- Mathematical physics. --- Physical mathematics --- Measuring --- Mensuration --- Mathematics --- Technology --- Metrology --- Physical measurements --- Measurements, Physical --- Mathematical physics --- Measurement --- Relativistic quantum field theory --- Field theory (Physics) --- Quantum theory --- Relativity (Physics)
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This thesis is based on the first data from the Large Hadron Collider (LHC) at CERN. Its theme can be described as the classical Rutherford scattering experiment adapted to the LHC: measurement of scattering angles to search for new physics and substructure. At the LHC, colliding quarks and gluons exit the proton collisions as collimated particle showers, or jets. The thesis presents studies of the scattering angles of these jets. It includes a phenomenological study at the LHC design energy of 14 TeV, where a model of so-called large extra dimensions is used as a benchmark process for the sensitivity to new physics. The experimental result is the first measurement, made in 2010, by ATLAS, operating at the LHC start-up energy of 7 TeV. The result is compatible with the Standard Model and demonstrates how well the physics and the apparatus are understood. The first data is a tiny fraction of what will be accumulated in the coming years, and this study has set the stage for performing these measurements with confidence as the LHC accumulates luminosity and increases its energy, thereby probing smaller length scales.
Momentum distributions. --- Physics. --- Proton-proton interactions. --- Quantum theory. --- Physics --- Earth & Environmental Sciences --- Physical Sciences & Mathematics --- Nuclear Physics --- Meteorology & Climatology --- Atomic Physics --- Collisions, Proton --- Interactions, Proton-proton --- Proton interactions --- Proton-proton collisions --- Distributions, Momentum --- Cosmology. --- Nuclear physics. --- Elementary particles (Physics). --- Quantum field theory. --- Particle and Nuclear Physics. --- Elementary Particles, Quantum Field Theory. --- Relativistic quantum field theory --- Field theory (Physics) --- Quantum theory --- Relativity (Physics) --- Elementary particles (Physics) --- High energy physics --- Nuclear particles --- Nucleons --- Nuclear physics --- Atomic nuclei --- Atoms, Nuclei of --- Nucleus of the atom --- Astronomy --- Deism --- Metaphysics --- Natural philosophy --- Philosophy, Natural --- Physical sciences --- Dynamics --- Angular momentum --- Nuclear reactions --- Quantum dynamics --- Quantum mechanics --- Quantum physics --- Mechanics --- Thermodynamics
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This book mainly focuses on the study of photon + 3 jets final state in Proton-Proton Collisions at √s = 7TeV, searching for patterns of two (or more) distinct hard scatterings in the same collision, i.e the so-called Double Parton Scattering (DPS). A new method by using Monte Carlo generators was performed and provides higher order corrections to the description of the Single Parton Scattering (SPS) background. Further it is investigated whether additional contributions from DPS can improve the agreement between the measured data and the Monte Carlo predictions. The current theoretical uncertainties related to the SPS background are found to be larger than expectation. At the same time a rich set of DPS-sensitive measurements is reported for possible further interpretation.
Physics. --- Nuclear physics. --- Heavy ions. --- Hadrons. --- Elementary particles (Physics). --- Quantum field theory. --- Particle acceleration. --- Nuclear Physics, Heavy Ions, Hadrons. --- Elementary Particles, Quantum Field Theory. --- Particle Acceleration and Detection, Beam Physics. --- Photons --- Proton-proton interactions. --- Scattering. --- Collisions, Proton --- Interactions, Proton-proton --- Proton interactions --- Proton-proton collisions --- Nuclear reactions --- Scattering (Physics) --- Quantum theory. --- Atomic nuclei --- Atoms, Nuclei of --- Nucleus of the atom --- Physics --- Particles (Nuclear physics) --- Acceleration (Mechanics) --- Nuclear physics --- Quantum dynamics --- Quantum mechanics --- Quantum physics --- Mechanics --- Thermodynamics --- Acceleration --- Relativistic quantum field theory --- Field theory (Physics) --- Quantum theory --- Relativity (Physics) --- Elementary particles (Physics) --- High energy physics --- Nuclear particles --- Nucleons --- Ions
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This thesis introduces readers to the Standard Model, the top quark and its properties, before explaining the concept of spin correlation measurement. The first measurement of top quark spin correlations at the LHC in the lepton+jets decay channel is presented. As the heaviest elementary particle, the top quark plays an essential role in the Standard Model of elementary particle physics. In the case of top quarks being produced in pairs at hadron colliders, the Standard Model predicts their spins to be correlated. The degree of correlation depends on both the production mechanism and properties of the top quark. Any deviation from the Standard Model prediction can be an indicator for new physics phenomena. The thesis employs an advanced top quark reconstruction algorithm including dedicated identification of the up- and down-type quarks from the W boson decay.
Physics. --- Elementary Particles, Quantum Field Theory. --- Quantum Field Theories, String Theory. --- Measurement Science and Instrumentation. --- Quantum theory. --- Physique --- Théorie quantique --- Physics --- Physical Sciences & Mathematics --- Nuclear Physics --- Atomic Physics --- Proton-proton interactions. --- Nuclear spin. --- Particles (Nuclear physics) --- Flavor. --- Spin, Nuclear --- Collisions, Proton --- Interactions, Proton-proton --- Proton interactions --- Proton-proton collisions --- Flavor (Nuclear physics) --- Flavor models (Nuclear physics) --- Top quark models --- Truth models (Nuclear physics) --- Quantum field theory. --- String theory. --- Elementary particles (Physics). --- Physical measurements. --- Measurement. --- Quarks --- Angular momentum (Nuclear physics) --- Nuclear physics --- Nuclear reactions --- Quantum dynamics --- Quantum mechanics --- Quantum physics --- Mechanics --- Thermodynamics --- Measurement . --- Measuring --- Mensuration --- Mathematics --- Technology --- Metrology --- Physical measurements --- Measurements, Physical --- Mathematical physics --- Measurement --- Models, String --- String theory --- Relativistic quantum field theory --- Field theory (Physics) --- Quantum theory --- Relativity (Physics) --- Elementary particles (Physics) --- High energy physics --- Nuclear particles --- Nucleons
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