Excitation functions for the 1n and 2n exit channels of the 208Pb(51V,xn)259-xDb reaction were measured. A maximum cross section of the 1n exit channel of 2070+1100/-760 pb was measured at an excitation energy of 16.0 +- 1.8 MeV. For the 2n exit channel, a maximum cross section of 1660+450/-370 pb was measured at 22.0 +- 1.8 MeV excitation energy. The 1n excitation function for the 209Bi(50Ti,n)258Db reaction was remeasured, resulting in a cross section of 5480+1730/1370 pb at an excitation energy of 16.0 +- 1.6 MeV. Differences in cross section maxima are discussed in terms of the fusion probability below the barrier. The extraction of niobium (Nb) and tantalum (Ta) from hydrochloric acid and mixed hydrochloric acid/lithium chloride media by bis(2-ethylhexyl) hydrogen phosphate (HDEHP) and bis(2-ethylhexyl) hydrogen phosphite (BEHP) was studied. The goal of the experiments was to find a system that demonstrates selectivity among the members of group five of the Periodic Table and is also suitable for the study of dubnium (Db, Z = 105). Experiments with niobium and tantalum were performed with carrier (10-6 M), carrier free (10-10 M) and trace (10-16 M) concentrations of metal using hydrochloric acid solution with concentrations ranging from 1 - 11 …

The WARP code is a robust electrostatic particle-in-cell simulation package used to model charged particle beams with strong space-charge forces. A fundamental operation associated with seeding detailed simulations of a beam transport channel is to generate initial conditions where the beam distribution is matched to the structure of a periodic focusing lattice. This is done by solving for periodic, matched solutions to a coupled set of ODEs called the Kapchinskij-Vladimirskij (KV) envelope equations, which describe the evolution of low-order beam moments subject to applied lattice focusing, space-charge defocusing, and thermal defocusing forces. Recently, an iterative numerical method was developed (Lund, Chilton, and Lee, Efficient computation of matched solutions to the KV envelope equations for periodic focusing lattices, Physical Review Special Topics-Accelerators and Beams 9, 064201 2006) to generate matching conditions in a highly flexible, convergent, and fail-safe manner. This method is extended and implemented in the WARP code as a Python package to vastly ease the setup of detailed simulations. In particular, the Python package accommodates any linear applied lattice focusing functions without skew coupling, and a more general set of beam parameter specifications than its predecessor. Lattice strength iteration tools were added to facilitate the implementation of problems with …

A search for the muon neutrino magnetic moment was conducted using the Mini-BooNE low energy neutrino data. The analysis was performed by analyzing the elastic scattering interactions of muon neutrinos on electrons. The analysis looked for an excess of elastic scattering events above the Standard Model prediction from which a limit on the neutrino magnetic could be set. In this thesis, we report an excess of 15.3 {+-} 6.6(stat){+-}4.1(syst) {nu}{sub {mu}e} events above the expected background. At 90% C.L., we derived a limit on the muon neutrino magnetic moment of 12.7 x 10{sup -10} {micro}{sub B}. The other analysis reported in this thesis is a measurement of charged current single pion production (CC{pi}{sup +}) to charged current quasi elastic (CCQE) interactions cross sections ratio. This measurement was performed with two different fitting algorithms and the results from both fitters are consistent with each other.

The top quark is the heaviest and most mysterious of the known elementary particles. Therefore, careful study of its production rate and other properties is of utmost importance for modern particle physics. The Tevatron is the only facility currently capable of studying top quark properties by on-shell production. Measurement of the top quark pair production cross section is one of the major goals of the Tevatron Run II physics program. It provides an excellent test of QCD at energies exceeding 100 GeV. We report on a new measurement of p{bar p} {yields} t{bar t} production at {radical} = 1.96 TeV using 350 pb{sup -1} of data collected with the D0 detector between 2002 and 2005. We focus on the final state where a W boson from one of the top quarks decays into a {tau} lepton and its associated neutrino, while the other decays into a quark-antiquark pair. We aim to select those events in which the {tau} lepton subsequently decays to one or three charged hadrons, zero or more neutral hadrons and a tau neutrino (the charge conjugate processes are implied in all of the above). The observable signature thus consists of a narrow calorimeter shower with associated track(s) …

This thesis studies the high-energy collisions of protons and antiprotons. The data used in the measurement were collected during 2004-2005 with the D0 detector at the Tevatron Collider of the Fermi National Accelerator Laboratory and correspond to 0.7 fb{sup -1} of integrated luminosity. High energy hadron collisions usually produce collimated sprays of particles called jets. The energy of the jets is measured using a liquid Argon-Uranium calorimeter and the production angle is determined with the help of silicon microstrip and scintillating fiber trackers. The inclusive jet cross section in proton-antiproton collisions is measured as a function of jet transverse momentum p{sub T} in six bins of jet rapidity at the center-of-mass energy {radical}s = 1.96 TeV. The measurement covers jet transerve momenta from 50 GeV up to 600 GeV and jet rapidities up to |y| = 2.4. The data are collected using a set of seven single jet triggers. Event and jet cuts are applied to remove non-physical backgrounds and cosmic-ray interactions. The data are corrected for jet energy calibration, cut and trigger efficiencies and finite jet p{sub T} resolution. The corrections are determined from data and the methods are tested with Monte Carlo simulation. The main experimental challenges in …

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The experimental study of rare decays of hadrons containing the b quark has been a fertile ground for some time, and keeps being one of the most interesting subjects in high energy physics. It has improved our understanding of hadronic processes, and allows investigating various aspects of the Standard Model and searching for hints of physics beyond the Standard Model. Examples are the comparison of branching fractions of charmless modes with predictions of models, the constraints on CKM angles (B{sup 0} {yields} {pi}{sup +}{pi}{sup -}, B {yields} DK, with D in suppressed modes), the observation of purely leptonic modes (B{sup {+-}} {yields} {tau}{sup {+-}}{nu}), the recently established difference in A{sub CP} between B{sup 0} {yields} K{sup +}{pi}{sup -} and B{sup {+-}} {yields} K{sup {+-}}{pi}{sup 0}, suspected to be a hint new physics. All of them came from a long and successful experimental activity with e{sup +}e{sup -} collisions at the {Upsilon}(4S) resonance. With hadronic colliders now coming into play, the study of rare decays is reaching new heights. Given the high cross section for production of all kinds of B hadrons, the record luminosities now provided by the Tevatron collider, and the LHC program in view for the next years, …

This analysis focuses on a low mass Higgs boson search with 1.7 fb{sup -1} of data. The focus is on Higgs events in which it is produced in association with a W or Z boson. Such events are expected to leave a distinct signature of large missing transverse energy for either a Z {yields} {nu}{nu} decay or a leptonic W decay in which the lepton goes undetected, as well as jets with taggable secondary vertices from the H {yields} b{bar B} decay. Utilizing a new track based technique for removing QCD multi-jet processes as well as a neural network discriminant, an expected limit of 8.3 times the Standard Model prediction at the 95% CL for a Higgs boson mass of 115 GeV/c{sup 2} is calculated, with an observed limit of 8.0*SM.

Supermassive black holes (SMBHs) are ubiquitous in the centers of galaxies. Their formation and subsequent evolution is inextricably linked to that of their host galaxies, and the study of galaxy formation is incomplete without the inclusion of SMBHs. The present work seeks to understand the growth and evolution of SMBHs through their interaction with the host galaxy and its environment. In the first part of the thesis (Chap. 2 and 3), we combine a simple semi-analytic model of outflows from active galactic nuclei (AGN) with a simulated dark matter density distribution to study the impact of SMBH feedback on cosmological scales. We find that constraints can be placed on the kinetic efficiency of such feedback using observations of the filling fraction of the Ly{alpha} forest. We also find that AGN feedback is energetic enough to redistribute baryons over cosmological distances, having potentially significant effects on the interpretation of cosmological data which are sensitive to the total matter density distribution (e.g. weak lensing). However, truly assessing the impact of AGN feedback in the universe necessitates large-dynamic range simulations with extensive treatment of baryonic physics to first model the fueling of SMBHs. In the second part of the thesis (Chap. 4-6) we …