The canonical quantization formalism is applied to the Lagrange density of chromodynamics in a general covariant gauge. The physical states are characterized by their BRS-invariance. We develop the quantum theory of the interacting fields in the Dirac picture, based on the Gell-Mann and Low Theorem and the Dyson expansion of the time evolution operator. Subsequently, confinement is introduced phenomenologically by imposing, on the quark, gluon and ghost field operators, the linear boundary conditions of the M.I.T. bag model at the surface of a spherically symmetric and static cavity. Based on this formalism, we calculate, in the Feynman gauge, all non-divergent Feynman diagrams of second order in the strong coupling constant g. Explicit values of the matrix elements are given for low-lying quark and gluon cavity modes.

We develop a number of new techniques and systems to be used in the design of beamlines for charged particle beam transport. A few of these refer specifically to beamlines to or from a cyclotron, while others may be used in beamlines from any accelerator. In the former category, we develop a method for determining the eigen-ellipsoid in all six dimensions of phase space, when the beam under consideration is to be (a) extracted from a cyclotron, or (b) injected into a cyclotron. We also develop an alternative method to (a) above, which uses the data derived from tracking (i) central momentum particles through the extraction elements of an accelerator in 4-dimensional (x, x´, y, y´) phase space and (ii) a single particle with higher momentum. For this purpose we expand the convenient E-matrix formalism from a 2-dimensional treatment to a 6-dimensional treatment, and relate this to the more usual σ-matrix formalism. We describe the eight possible symmetry types of beams transport systems and examine their group properties. We also examine the second-order aberrations in these systems. We use the symmetry properties to examine various configurations of two quadrupole triplets. This system may be used to achieve unit magnification, as is well known: or variable magnification in one or both of the horizontal or vertical planes, independently of the beam parameters, as we describe. We also develop a system of quadrupoles which may be used for independent horizontal and vertical beam control. We calculate the optimum spacing and field strength of these quadrupoles. Dipole systems which are used to control the dispersed rays are discussed. In particular we consider a system of two quadrupoles between two dipoles: this system has the least number of beamline elements necessary to control the position and direction of the dispersed ray while simultaneously permitting momentum-selection. We discuss the principles of transfer beamline design and illustrate these (and the techniques described above) by reference to the design of a specific transfer beamline between cyclotrons. The design of a specific external beamline is also described and used to illustrate the techniques developed.

The object of this investigation was to determine the effect of acceleration on the drag of spheres as it differs from the steady state case. Steady state drag applies to the force acting on a single sphere moving at constant velocity through an infinite, continuous, incompressible, turbulence free fluid. Extensive experimentation has quite thoroughly documented the steady state drag characteristics of spheres. A dimensionless parameter associated with the drag force is sometimes used to correlate drag characteristics.

In this work the methods of exact quantum number conservation in statistical mechanics are discussed and applied to the field of high energy nucleus-nucleus collisions. Various types of hadronic gas models are discussed as well as their merits and restrictions. Attempts to construct a phenomenological equation of state for nuclear matter are discussed in the context of the phase transition from hadronic matter to the quark-gluon plasma (QGP).

Same-sign W-boson scattering is a rare Standard Model process that is useful for probing the nature of electroweak symmetry breaking and the Higgs mechanism. Analysis is currently underway to measure the cross-section to a significance of 5σ or higher using √s = 13 TeV data from the ATLAS detector's Run 2. The two scattered W-bosons decay leptonically leaving a distinctive experimental signature of two same-sign leptons, two forward jets, and missing transverse energy carried away by two neutrinos. Non-prompt leptons are defined as leptons coming from the decay of hadrons. Such leptons, together with jets misreconstructed as leptons, contribute to the background processes in same-sign W-boson scattering; making up the so-called fake lepton background. In this thesis the fake lepton background is suppressed using two strategies: 1) implementing an optimised veto on events found to contain a b-jet; and 2) optimising the isolation requirements set on signal lepton candidates using the cumulative significance quantity. The approach using the cumulative significance is then extended to optimise additional analysis cuts on the lepton invariant mass mₗₗ, jet invariant mass mⱼⱼ , and the jet separation rapidity Δyⱼⱼ.

The ATLAS detector is a multipurpose particle detector built to record almost all possible decay products of the high energy proton-proton collisions provided by the Large Hadron Collider. The presence and combined kinematics of unobserved particles can be inferred by the observed momentum imbalance in the transverse plane. In this work, a deep neural network was trained using supervised learning to measure this imbalance. The performance of this network was evaluated in MC simulation and in 43 fb⁻¹ of data recorded at ATLAS. The network offered superior resolution and significantly better pileup resistance than all other pre-existing algorithms in every tested topology. The network also provided the best discriminator between events that did and did not contain neutrinos. The potential gain insensitivity to new physics was demonstrated by using this network in a search for the electroweak production of supersymmetric particles. The expected sensitivity to observe the production of said particles was increased by up to 26%.

Bibliography: p. 67-69. / Using the Time-of-Flight facility at the National Accelerator Centre at Faure, the (p, n) charge-exchange reaction has been studied at intermediate energies of 120, 160 and 200 MeV, and at angles of 0°, 2° and 4°. In this work the data collected for the ⁹⁰Zr target will be presented. The influence on the data from slow neutrons due to previous pulses is discussed and the best manner of removing them from the spectra is recommended. It is shown how the background cosmic rays can be utilised to measure the intrinsic resolution of the detectors and to obtain an estimate of the neutron energy threshold. The differential cross-sections for the states corresponding to Fermi and Gamow-Teller transitions were extracted from the time spectra. The sum of the strength of all the discrete Gamow-Teller states was determined and compared to the Ikeda Sum Rule. It was found that only 50% of the sum could be accounted for in the discrete states. An overview of the theory that has been developed to extract Gamow-Teller strengths from the (p, n) cross-sections is given. Some of the theoretical models that have been used to describe the ⁹⁰Zr(p, n)⁹⁰ Nb reaction and account for the missing Gamow-Teller strength are briefly discussed.

Includes bibliographical references and index. / A Hadron Gas model, including resonance decays, is used to predict momentum spectra and particle ratios. The model, including all significant two and three body resonance decays, is compared with transverse momentum spectra from the CERN-SPS NA44 Pbr Pb experiment and the implications of the fits are discussed. It is shown that resonance decays fail to explain the low mT anomaly in the pion transverse momentum spectrum. The effects of resonance decays are then considered in the calculation of various particle ratios. The width of the rapidity window is varied and its effect on the particle ratios is examined.

A crystal of the carbon-rich phosphor, anthracene, has been bombarded by monoenergetic fast neutrons. Alpha-particle decays of carbon nuclei have been separated from other events by a specialised application of the pulse shape discrimination technique. A numerical analysis of the data has yielded alpha-particle energy spectra over a wide energy range. A counter has been assembled to detect neutrons scattered by carbon nuclei in the crystal, and the measurements repeated in coincidence with these neutrons. The energy range of particle resolving power has been extended. Structure in the resulting alpha-particle and proton energy spectra is attributed to particle decays of specific levels in carbon-12. It is shown how the experiment may be modified and extended to measure decay parameters in absolute terms.

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