No description available.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. August 11, 2014. / The Z' gauge boson is a hypothetical neutral particle of spin-1 appearing in many theories beyond the Standard Model. In the context of the Z' boson of the Sequential Standard Model in the hadronic decay channel Z' ThadThad, this project investigates improving the sensitivity of the analysis. It is important in the analysis to have high signal e ciency and to be able to distinguish against background processes, thus this project begins with an investigation into new triggers and their combinations that aim to improve the signal e ciency, followed by a study to improve the tau identi cation using tracking. Monte Carlo samples were compared with the data sample for various cut-based variables to investigate which of the variables o er a good discrimination power against the multijet background. The signi cance of each trigger and trigger combinations are shown, as well as the performance of di erent techniques and ideas used to improve the tau identi cation using tracking. Since it is important in this project to be able to reconstruct a tau lepton from its hadronic decay products, this dissertation takes the opportunity to present preliminary results on the study of the light collection uniformity and response in the crack scintillation counters of the ATLAS hadronic tile calorimeter as part of the contribution towards the detector upgrade.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 126-132).

Zugl.: Potsdam, Univ., Magisterarbeit, 2006

The N/Z, or ratio of neutron to proton, degree of freedom may be used to study intermediate energy nuclear collisions to give information about the origin of emitted collision fragments. Establishing under what conditions the onset of N/Z equilibrium occurs will give a better understanding of the physics of the equation of state through the use of simulation codes. If the nuclear equation of state can be elucidated in terms of the N/Z dependent component and how the N/Z dependent component varies with density, then the equilibrium ratio of protons to neutrons inside high density neutron stars can be inferred, allowing for prediction of cooling rates and supernovae mechanisms. In the current study, isotopic and isobaric ratios at thetalab=40o with cuts of 10% and 20% most central events, respectively, are studied for their N/Z equilibration signals. Light charged particles, or LCPs, are found to be emitted from systems which have not yet fully N/Z combined; the fragments with A=3 are emitted from the least equilibrated systems. Intermediate mass fragments, or IMFs, are seen to be emitted by N/Z equilibrated sources, within statistical error bars. The N/Z tracer method is used with ratios of isotopes and isobars to see how the amount of nuclear stopping or N/Z mixing changes as a function of the centrality of the event. The N/Z observable is used to reinvestigate earlier findings of the isotope and isobar ratio observables and shows the progression (or lack of it, in some cases) of the N/Z equilibration. This observable has proven to be a clear and sensitive tool to use when considering the differences in N/Z mixing of the systems at two energies.

No description available.

Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 318-345).

This work was supported by a National Science Foundation fellowship

This work was supported by a National Science Foundation fellowship.

The analytical solution presented in this thesis is based on the Liquid Metal Experiment (LEX) at Virginia Tech to determine the practicality of replacing a solid metal electrode with a liquid metal electrode wall. Replacing the solid metal with a liquid metal may improve the operational lifetime of Z-pinches. The LEX is based upon the University of Washington's High Energy Density Z-pinch (ZaP-HD) and Fusion Z-Pinch Experiments (FuZE) and replaces one solid metal electrode with a liquid metal electrode. During the operation of the ZaP-HD and FuZE, a plasma column exerts electromagnetic forces and pressure on a solid electrode wall. The pressure exerted by the plasma column is called the magnetic pressure. In the Virginia Tech device magnetic pressure is exerted by a wire onto the liquid metal electrode. The magnetic pressure in the LEX displaces the liquid metal electrode free surface, and subsequently creates a waveform. The initial free surface displacement and subsequent wave motion of the liquid metal is found by analyzing the geometry of the device, the electromagnetic forces generated during operation, and material properties of the tin-bismuth liquid metal mixture. The initial displacement for changing current, current pulse length, tin percentage, and applied pressure range are investigated. The results are compared for verification and validation. These methods are shown to be accurate to within an order of magnitude and are valid for an axisymmetric domain. The results presented here may inform further experimentation and aid in improving designs for newer devices. / Master of Science / This thesis presents analytical solutions for creating waveforms in liquid metal due to electromagnetic forces. The motivation for developing the analytical solutions is to aid in developing a device created by Virginia Polytechnic and State University (Virginia Tech). The Liquid Metal Experiment (LEX) at Virginia Tech investigates the practicality of incorporating a liquid metal into a Z-pinch fusion device under development at the University of Washington's High Energy Density Z-pinch (ZaP-HD) and Fusion Z-Pinch Experiments (FuZE). The ZaPHD and FuZE experiments are cylindrical and aim to investigate the viability of Z-pinches as fusion devices. An electric current passes between an internal electrode, the plasma column, and an external electrode along the z-axis of the Z-pinch. The time duration of the current is typically on the order of tens of microseconds. The plasma column and subsequent fusion events are generated only during this duration. During this duration, the interactions between the plasma column and the electrodes cause the electrodes to deteriorate. In standard Z-pinch devices, the electrodes are solid metal and deteriorate during the operation, limiting the device's lifespan. The liquid metal introduces other complexities to the system. During the time duration of the current, the electromagnetic forces produce a pressure gradient at the free surface of the liquid metal. The pressure created by the electromagnetic forces generates waveforms within the liquid metal. The analytical solutions presented in this thesis include electrodynamic solutions to find the pressure, kinematic solutions to determine the free surface displacement of the liquid metal due to the pressure, and fluid dynamic solutions of the waveform caused by the initial free surface displacement.