A micropatterned electrode was prepared for the study of electrocrystallization. Using microphotolithography, in conjunction with evaporation and pulse electrodeposition of thin films, a set of artificially roughened electrodes with hemispherical surface features five microns in diameter was developed. Voltammetric studies were conducted to determine the best electrode material. Gold, platinum, and various carbon surfaces were evaluated for zinc nucleation density and hydrogen overpotential. Surface homogeneity was examined by both light and scanning electron microscopy. Gold was determined to possess the best combination of material properties: chemical inertness, low melting point, and a high work function allowing underpotential deposition of zinc which reduces the rate of hydrogen evolution. Stripping coulometry was employed to determine zinc limiting currents, and evaluate effective diffusion coefficients in concentrated zinc chloride solutions. Although the method worked well for dilute zinc chloride and copper sulfate solutions, it failed at higher current densities; the emergence of surface roughness obscured actual limiting current plateaus.

The theory that describes the fundamental particle interactions is called the Standard Model, which is a gauge field theory that comprises the Glashow-Weinberg-Salam model [1, 2, 3] of the weak and electromagnetic interactions and quantum chromodynamics (QCD) [4, 5, 6], the theory of the strong interactions. The discovery of the W [7, 8] and Z [9, 10] bosons in 1983 by the UA1 and UA2 collaborations at the CERN p{bar p} collider provided a direct confirmation of the unification of the weak and electromagnetic interactions. Since then, many experiments have refined our understanding of the characteristics of the W and Z bosons.

The observation of multiple-quantum nuclear magnetic resonance transitions in isotropic or anisotropic liquids is shown to give readily interpretable information on molecular configurations, rates of motional processes, and intramolecular interactions. However, the observed intensity of high multiple-quantum transitions falls off dramatically as the number of coupled spins increases. The theory of multiple-quantum NMR is developed through the density matrix formalism, and exact intensities are derived for several cases (isotropic first-order systems and anisotropic systems with high symmetry) to shown that this intensity decrease is expected if standard multiple-quantum pulse sequences are used. New pulse sequences are developed which excite coherences and produce population inversions only between selected states, even though other transitions are simultaneously resonant. One type of selective excitation presented only allows molecules to absorb and emit photons in groups of n. Coherent averaging theory is extended to describe these selective sequences, and to design sequences which are selective to arbitrarily high order in the Magnus expansion. This theory and computer calculations both show that extremely good selectivity and large signal enhancements are possible.

The authors performed a search for the pair production of first-generation leptoquarks using 191 pb{sup -1} of proton-antiproton collision data recorded by the CDF experiment during Run II of the Tevatron. The leptoquarks are sought via their decay into a neutrino and quark, which yields missing transverse energy and several high-E{sub T} jets. Several control regions were studied to check the background estimation from Standard Model sources, with good agreement observed in data. In the leptoquark signal region, 124 events were observed with 118.3 {+-} 14.5 expected from background. Therefore, no evidence for leptoquark production was observed, and limits were set on the cross section times the squared branching ratio. Using the next-to-leading order cross section for leptoquark production, they excluded the mass interval 78 to 117 GeV/c{sup 2} at the 95% confidence level for 100% branching ratio into neutrino plus quark.

In the Tevatron accelerator at Fermilab protons and antiprotons are collided at a 1.96 TeV center of mass energy. CDF and D0 are the two experiments currently operating at the Tevatron. At these energies top quark is mostly produced via strong interactions as a top anti-top pair (t{bar t}). The top quark has an extremely short lifetime and according to the Standard Model it decays with {approx} 100% probability into a b quark and a W boson. In the ''lepton+jets'' channel, the signal from top pair production is detected for those events where one of the two W bosons decays hadronically in two quarks which we see as jets in the detector, and the other W decays into an electrically charged lepton and a neutrino. A relatively unambiguous identification in the detector is possible when we require that the charged lepton must be an electron or muon of either charge. The neutrino does not interact in the detector and its presence is inferred from an imbalance in the transverse energy of the event. They present a measurement of the top pair production cross section in p{bar p} collisions at 1.96 TeV, from a data sample collected at CDF between March …

We present results on a search for Gauge Mediated Supersymmetry in the di-photon final state using Run II data collected by the D0 Experiment at the Fermilab Tevatron Collider. We discuss event selection, Standard Model backgrounds, and the lower limits on the lightest neutralino and chargino masses resulted from this analysis.

The Higgs mechanism preserves the gauge symmetries of the Standard Model while giving masses to the W, Z bosons. Supersymmetry, which protects the Higgs boson mass scale from quantum corrections, predicts at least 5 Higgs bosons, none of which has been directly observed. This thesis presents a search for neutral Higgs bosons, produced in association with bottom quarks. The production rate is greatly enhanced at large values of the Supersymmetric parameter tan {beta}. High-energy p{bar p} collision data, collected from Run II of the Fermilab Tevatron using the D0 detector, are analyzed. In the absence of a signal, values of tan {beta} > 80-120 are excluded at 95% Confidence Level (C.L.), depending on the (CP-odd) neutral Higgs boson mass (studied from 100 to 150 GeV/c{sup 2}).

The authors present a measurement of the {bar p}p {yields} W{gamma} + X {yields} e{nu}{gamma} + X production cross section using data form the Collider Detector at Fermilab. The p{bar p} collisions were provided by the Tevatron Collider at a center of mass energy of 1.96 TeV. Electroweak theory includes the trilinear vector boson coupling, WW{gamma}, which contributes to the e{nu}{gamma} final state. The electron decay channel of the W provides a clean sample to study the production of diboson pairs. The measurement of the production cross section tests the structure of the non-Abelian character of Electroweak theory.

A measurement of the t{bar t} pair production cross section is presented using 162 pb{sup -1} of data collected by the CDF experiment during Run II at the Tevatron. t{bar t} events in the lepton+jets channel are isolated by identifying electrons and muons, reconstructing jets and transverse missing energy, and identifying b jets with a secondary vertex tagging algorithm. The efficiency of the algorithm is measured in a control sample using a novel technique that is less dependent on the simulation. For a top quark mass of 175 GeV/c{sup 2}, a cross section of {sigma}{sub t{bar t}} = 5.6{sub -1.1}{sup +1.2}(stat.){sub -0.6}{sup +0.9}(syst.)pb is measured.

A measurement of the t{bar t} production cross section in the lepton+jets channels with the D0 detector at {radical}s = 1.96 TeV using the lifetime-tagging techniques is presented. The t{bar t} cross section is estimated from the combination of the e+jets and {mu}+jets channels. The obtained result {sigma}{sub t{bar t}} = 7.47{sub -1.14}{sup +1.22}(stat){sub -1.03}{sup +1.65}(syst) {+-} 0.49(lumi) pb is consistent with the Standard Model expectation.

The first measurement of the top-antitop production cross section in proton-antiproton collisions at {radical}s = 1.96 TeV using 243 pb{sup -1} of data collected with the D0 detector at Fermilab is presented. In this analysis, only the dielectron final state is considered. Five events are observed, and 0.93 background events are expected. The measured cross section, after accounting for the expected branching ratio to the dielectron channel, is {sigma}{sub t{bar t}} = 14.9{sub -7.0}{sup +9.4}(stat){sub -1.8}{sup +2.5}(syst) {+-} 1.0 (lumi) pb, which agrees with the predicted cross section for top quarks with a mass of 175 GeV. In addition, a first-pass at a measurement of the top mass using the neutrino-weighting method is presented. This measurement is also performed in the dielectron channel using the five events observed in the cross section measurement.

This document presents a measurement of the top quark mass using the CDF run II detector at Fermilab. Colliding beams of protons and anti-protons at Fermilab's Tevatron ({radical}s = 1.96 TeV) produce top/anti-top pairs, which decay to W{sup +}W{sup -} b{bar b}; events are selected where one W decays hadronically, and one W decays to either e or {mu} plus a neutrino. The data sample was collected between March 2002 and September 2003, and corresponds to an integrated luminosity of approximately 162 pb{sup -1}. Thirty-seven candidate t{bar t} events are found with at least one b jet identified by its displaced vertex. In each event, the best fit top quark invariant mass is determined by minimizing a {chi}{sup 2} for the overconstrained kinematic system. A likelihood fit of the reconstructed masses in the data sample to distributions from simulated signal and background events gives a top mass of 174.9{sub -7.7}{sup +7.1}(stat.) {+-} 6.5(syst.) GeV/c{sup 2}. The dominant systematic error is due to uncertainties in the jet energy measurements.

A measurement of the inclusive Z/{gamma}* {yields} {mu}{sup +}{mu}{sup -} cross section for M{sub {mu}{mu}} > 40 GeV at {radical}s = 1.96 TeV is presented. The measurement is performed using a data sample corresponding to an integrated luminosity of 147.7 pb{sup -1}, collected with the D0 detector at the Tevatron, Fermilab, between September 2002 and October 2003. A total of 14352 di-muon events are selected and a final result of {sigma}(Z/{gamma}*) = 327.8 {+-} 3.4(stat.) {+-} 8.4(syst.) {+-} 21.3(lumi.) pb is obtained. Correcting the number of di-muon events by a factor of 0.885 {+-} 0.015 for the contribution from pure {gamma}* exchange and Z/{gamma}* interference, the inclusive Z {yields} {mu}{sup +}{mu}{sup -} cross section is found to be: {sigma}(Z) = 290.1 {+-} 3.0(stat.) {+-} 7.4(syst.) {+-} 18.9(lumi.) pb. Finally, comparisons of W and Z boson p{sub T} distributions as measured with D0 during Run I of the Tevatron are compared to HERWIG and MC{at}NLO predictions. Relevant parameters in the simulations are tuned to obtain the best possible fit to the data. An excellent agreement is found for both HERWIG and MC{at}NLO.

The D0 experiment, located at the Fermilab National Accelerator Laboratory in the US, is used to study proton-anti-proton collisions at a center of mass energy of 1.96 TeV. The experiment's data acquisition system is based on a sophisticated trigger system used to select potentially interesting events. The Level 2 Silicon Track Trigger (L2STT) is part of the trigger system that provides precise reconstruction of charged particle tracks allowing the selection of events that contain the decays of long lived particles. For example, such particles appear in the decay of the Higgs boson into a pair of bottom quarks. The design of the L2STT preprocessor has greatly benefited from recent advances in electronics technology. The preprocessor has been recently installed and will be used to further optimize the triggering strategy of the experiment. Leptoquarks would mediate hypothetical new interactions between the quarks and leptons of the Standard Model. The existence of such particles would be evidence for physics beyond that model. In this thesis, a direct search for leptoquarks is performed in the jets and missing transverse energy final state. For this analysis, a trigger had to be developed along with a tool to precisely determine its efficiency. An analysis of …

The magnetic properties of quenched and annealed powder specimens of MnPt were investigated using x-ray diffraction, magnetization measurements and neutron diffraction techniques. Thin films of MnPt were prepared by rf sputtering techniques and the films were investigated by x-ray diffraction and magnetization measurements. The powder specimens of MnPt were found to be typically antiferromagnetic in an L1/sub 0/ structure with Mn atoms occupying the (001) planes. The Mn moments were antiparallel to their nearest neighbors in the (001) planes. The atomic moment of Mn is (4.1 +- .2) ..mu../sub B/ for the annealed specimens and (3.9 +- .2) ..mu../sub B/ for the quenched specimens. Neutron data failed to determine whether or not Pt carries a moment. Assuming a moment associated with the Pt atoms, the maximum value is 0.2 ..mu../sub B/ per atom. The quenched specimens contained small ferromagnetic regions probably with a composition of 18-32 at. percent Mn. The sputtered films of MnPt were highly disordered in all but one specimen, which was amorphous. The films were ferromagnetic with the deduced Mn moment of (3.0 +- .3) ..mu../sub B/ per atom, which may not represent the true value because the films were not entirely ferromagnetic.

Two alternative measurements of the t{bar t} production cross section at {radical}s = 1.96 TeV in proton-antiproton collisions in the lepton+jets channel are presented. The t{bar t} production cross section is extracted by combining the kinematic event information in a multivariate discriminant. The measurement yields {sigma}{sub p{bar p} {yields} t{bar t} + x} = 5.13{sub -1.57}{sup +1.76}(stat){sub -1.10}{sup +0.96}(syst) {+-} 0.33 (lumi) pb in the muon+jets channel, using 229.1 pb{sup -1}, and in the combination with the electron+jets channel 226.3 pb{sup -1} {sigma}{sub p{bar p} {yields} t{bar t} + x} = 6.60{sub -1.28}{sup +1.37}(stat){sub -1.11}{sup +1.25}(syst) {+-} 0.43 (lumi) pb. The second measurement presented reconstructs explicitly secondary vertices to d lifetime b-tagging. The measurement combines the muon+jets and the electron+jets channel, using 158.4 pb{sup -1} and 168.8 pb{sup -1}, respectively: {sigma}{sub p{bar p} {yields} t{bar t} + x} = 8.24{sub -1.25}{sup +1.34}(stat){sub -1.63}{sup +1.89}(syst) {+-} 0.54 (lumi) pb.

The production of heavy quarkonium in hadronic collisions provides an ideal testing ground for our understanding of the production mechanisms for heavy quarks and the non-perturbative QCD effects that bind the quark pairs into quarkonium. In this analysis, the inclusive production cross section of the {Upsilon}(1S) bottomonium state is measured using the {Upsilon}(1S) {yields} {mu}{sup +}{mu}{sup -} decay mode. The data sample corresponds to an integrated luminosity of 159.1 {+-} 10.3 pb{sup -1}. We determine differential cross sections as functions of the {Upsilon}(1S) transverse momentum, p{sub T}{sup {Upsilon}}, for three ranges of the {Upsilon}(1S) rapidity: 0 < |y{sup {Upsilon}}| < 0.6,0.6 < |y{sup {Upsilon}}| < 1.2 and 1.2 < |y{sup {Upsilon}}| < 1.8. The shapes of d{sigma}/d{sub p{sub T}} cross sections show little variation with rapidity and are consistent with the published Run I CDF measurement over the rapidity range |y{sup {Upsilon}}| < 0.4.

None

This thesis consists of two parts: In the first part we describe the Photomultiplier Tube (PMT) selection and testing processes for the Hadronic Forward (HF) calorimeter of the CMS, a Large Hadron Collier (LHC) experiment at CERN. We report the evaluation process of the candidate PMTs from three different manufacturers, the complete tests performed on the 2300 Hamamatsu PMTs which will be used in the HF calorimeter, and the details of the PMT Test Station that is in University of Iowa CMS Laboratories. In the second part we report the {Xi}{sub c}{sup +} lifetime measurement from SELEX, the charm hadro-production experiment at Fermilab. Based upon 301 {+-} 31 events from three di.erent decay channels, by using the binned maximum likelihood technique, we observe the lifetime of {Xi}{sub c}{sup +} as 427 {+-} 31 {+-} 13 fs.

In this dissertation, we measure the properties of the lowest-mass beauty baryon, {Lambda}{sub b}. Baryons are the bound states of three quarks. Protons and neutrons, constituents of atomic nuclei, are the most common baryons. Other types of baryons can be produced and studied in the high-energy collider environment. Three-body dynamics makes baryons composed of low mass quarks difficult to study. On the other hand, baryons with one heavy quark simplify the theoretical treatment of baryon structure, since the heavy quark can be treated the same way as the nucleus in the atom. The {Lambda}{sub b} is composed of u, d, and b quarks, where the b quark is much heavier than the other two. Although, it is accessible, little is known about {Lambda}{sub b}. In 1991, UA1 [1] reconstructed 9 {+-} 1 {Lambda}{sub b} {yields} J/{Psi}{Lambda} candidates. In 1996, ALEPH and DELPHI reconstructed the decay {Lambda}{sub b} {yields} {Lambda}{sub c}{sup +}{pi}{sup -} and found only 3-4 candidates [2, 3]. ALEPH measured a {Lambda}{sub b} mass of 5614 {+-} 21 MeV/c{sup 2}, while DELPHI measured 5668 {+-} 18 MeV/c{sup 2}, about 2 {sigma} higher. Subsequently, CDF-I observed 20 {Lambda}{sub b} {yields} J/{Psi}{Lambda} events [4], confirmed the existence of {Lambda}{sub b} unambiguously …

The authors have performed a search for the scalar bottom quark ({tilde b}{sub 1}) from gluino ({tilde g}) decays in an R-parity conserving SUSY scenario with m{sub {tilde g}} > m{sub {tilde b}{sub 1}}, by investigating a final state of large missing transverse energy, with three or more jets, and some of them from the hadronization of b-quarks. A data sample of 156 pb{sup -1} collected by the Collider Detector at Fermilab at a center-of-mass energy of {radical}s = 1.96 TeV was used. For the final selection, jets containing secondary displaced vertices were required. This analysis has been performed ''blind'', in that the inspection of the signal region was only made after the Standard Model prediction was finalized. Comparing data with SUSY predictions, they can exclude masses of the gluino and sbottom of up to 280 and 240 GeV/c{sup 2} respectively.

We present the results of a search for new particles decaying to tau pairs using the data corresponding to an integrated luminosity of 195 pb{sup -1} collected from March 2002 to September 2003 with the CDF detector at the Tevatron. Hypothetical particles, such as Z' and MSSM Higgs bosons can potentially produce the tau pair final state. We discuss the method of tau identification, and show the signal acceptance versus new particle mass. The low-mass region, dominated by Z {yields} {tau}{tau}, is used as a control region. In the high-mass region, we expect 2.8 {+-} 0.5 events from known background sources, and observe 4 events in the data sample. Thus no significant excess is observed, and we set upper limits on the cross section times branching ratio as a function of the masses of heavy scalar and vector particles.

High-precision measurements are made of Z boson production in proton-antiproton collisions at {radical}s = 1.96 TeV recorded by the Collider Detector at Fermilab, using the electron decay channel. The cross-section times branching ratio is measured to be {sigma}{sub Z} {center_dot} Br(Z {yields} e{sup +}e{sup -}) = (255.7 {+-} 2.4{sub stat} {+-} 5.2{sub sys} {+-} 15.2{sub lum})pb in a dataset of 194 pb{sup -1} collected between March 2002 and June 2003. This agrees well with theoretical predictions. The cross-section for W boson production in the electron channel has also been measured in the subset of this dataset of 72 pb{sup -1} collected up until January 2003. Using this smaller dataset the ratio of cross-sections is determined to be R {equivalent_to} {sigma}{sub W} {center_dot} Br(W {yields} e{nu})/{sigma}{sub Z} {center_dot} Br(Z {yields} ee) = 10.82 {+-} 0.18{sub stat} {+-} 0.16{sub sys}. Combining these results with measurements made in the muon channel gives R = 10.92 {+-} 0.15{sub stat} {+-} 0.14{sub sys} (e + {mu} channels), from which the branching ratio of the W to electrons and muons, and the total width of the W, have been extracted: Br(W {yields} {ell}{nu}) = 0.1089 {+-} 0.0022 ({ell} = e,{mu}); {Lambda}(W) = 2078.8 {+-} 41.4 MeV, …

The b quark fragmentation distribution has been measured, using data registered by the DELPHI experiment at the Z pole, in the years 1994-1995. The measurement made use of 176000 inclusively reconstructed B meson candidates. The errors of this measurement are dominated by systematic effects, the principal ones being related to the energy calibration. The distribution has been established in a nine bin histogram. Its mean value has been found to be <x{sub E}> = 0.704 {+-} 0.001(stat.) {+-} 0.008(syst.). Using this measurement, and other available analyses of the b-quark fragmentation distribution in e{sup +}e{sup -} collisions, the non-perturbative QCD component of the distribution has been extracted independently of any hadronic physics modeling. This distribution depends only on the way the perturbative QCD component has been defined. When the perturbative QCD component is taken from a parton shower Monte-Carlo, the non-perturbative QCD component is rather similar with those obtained from the Lund or Bowler models. When the perturbative QCD component is the result of an analytic NLL computation, the non-perturbative QCD component has to be extended in a non-physical region and thus cannot be described by any hadronic modeling. In the two examples, used to characterize these two situations, which are …