This thesis presents an indirect measurement of the width of the W boson using data collected at the D0 experiment, a multipurpose particle detector utilizing the Fermilab Tevatron. The W width was determined from the ratio of W {yields} {mu}{nu} to Z {yields} {mu}{sup +}{mu}{sup -} cross sections to be {Gamma}{sub W} = 2168 {+-} 22(stat) {+-} 62(syst){sub -16}{sup +24}(pdf) {+-} 4(other) MeV, in good agreement with the Standard Model prediction and other experimental measurements. In addition there is a description of how work made towards this measurement has been used to improve the parameterized detector simulation, a vital tool in the obtention of physics results from signals observed in the detector, and in estimating the uncertainty due to choice of PDF, which is of interest for all measurements made at hadron colliders.

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The MARO pilot project represents the first effort in the country to seek to obtain credit under a Clean Air Act (CAA) State Implementation Plan (SIP) for nitrogen oxide (NOx) emission reductions.

We present the results of an optical and near-IR spectroscopic study of giant nebular emission line halos associated with three z > 3 radio galaxies, 4C 41.17, 4C 60.07 and B2 0902+34. Previous deep narrow band Ly{alpha} imaging had revealed complex morphologies with sizes up to 100 kpc, possibly connected to outflows and AGN feedback from the central regions. The outer regions of these halos show quiet kinematics with typical velocity dispersions of a few hundred km s{sup -1}, and velocity shears that can mostly be interpreted as being due to rotation. The inner regions show shocked cocoons of gas closely associated with the radio lobes. These display disturbed kinematics and have expansion velocities and/or velocity dispersions >1000 km s{sup -1}. The core region is chemically evolved, and we also find spectroscopic evidence for the ejection of enriched material in 4C 41.17 up to a distance of {approx} 60 kpc along the radio-axis. The dynamical structures traced in the Ly{alpha} line are, in most cases, closely echoed in the Carbon and Oxygen lines. This shows that the Ly{alpha} line is produced in a highly clumped medium of small filling factor, and can therefore be used as a tracer of the …

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A search for direct production of scalar bottom quarks ({bar b}) is performed with 310 pb{sup -1} of data collected by the D0 experiment in p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron Collider. The topology analyzed consists of two b jets and an imbalance in transverse momentum due to undetected neutralinos ({tilde {chi}}{sub 1}{sup 0}), with {tilde {chi}}{sub 1}{sup 0} assumed to be the lightest supersymmetric particle. They find the data consistent with standard model expectations, and set a 95% C.L. exclusion domain in the (m{sub {tilde b}}, m{sub {tilde {chi}}}) mass plane, improving significantly upon the results from Run I of the Tevatron.

We present a study of events with Z bosons and jets produced at the Fermilab Tevatron Collider in p{bar p} collisions at a center of mass energy of 1.96 TeV. The data sample consists of nearly 14,000 Z/{gamma}* {yields} e{sup +}e{sup -} candidates corresponding to the integrated luminosity of 340 pb{sup -1} collected using the D0 detector. Ratios of the Z/{gamma}* + {ge} n jet cross sections to the total inclusive Z/{gamma}* cross section have been measured for n = 1 to 4 jet events. Our measurements are found to be in good agreement with a next-to-leading order QCD calculation and with a tree-level QCD prediction with parton shower simulation and hadronization.

We present a technique that allows for the simultaneous acquisition and interpretation of both shear-wave and compressive-wave 3-D velocities. The technique requires no special seismic sources or array geometries, and is suited to studies with small source-receiver offsets. The method also effectively deals with unwanted seismic arrivals by using the statistical properties of the data itself to discriminate against spurious picks. We demonstrate the technique with a field experiment at the Facility for Analysis, Calibration, and Testing at Sandia National Laboratories, Albuquerque, New Mexico. The resulting 3-D shear-velocity and compressive-velocity distributions are consistent with surface geologic mapping. The averaged velocities and V{sub p}/V{sub s} ratio in the upper 30 meters are also consistent with examples found in the scientific literature.

We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).

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