The resonant production of tau-lepton pairs is as interesting for the study of Standard Model (SM) physics as the production of lighter leptons pairs. For new phenomena, such as Higgs boson production or in case new particles beyond the SM would arise, the detection of (resonant) pairs of tau leptons becomes much more interesting. This is due to the fact that tau leptons are much heavier than the other leptons, which increases the chance that these new phenomena would be observed first in this channel. Unfortunately their clean detection is far more difficult than that of muons or electrons. The cross section times branching ratio {sigma}{center_dot} Br for the process p{bar p} {yields} Z {yields} {tau}{sup +}{tau}{sup -} was measured at {radical}s = 1.96 GeV using 1.0 fb{sup -1} of data collected by the D0 experiment. This measurement was performed in the channel in which one of the tau leptons decays to a muon and neutrinos, while the other decays either hadronically or to an electron and neutrinos. A set of 1511 events, of which about 20% estimated background, passed all selection criteria. The trigger and muon reconstruction efficiencies, as well as the efficiency for track reconstruction were obtained from …

A measurement of hadron production cross-sections for the simulation of accelerator neutrino beams and a search for muon neutrino to electron neutrino oscillations in the {Delta}m{sup 2} {approx} 1 eV{sup 2} region. This dissertation presents measurements from two different high energy physics experiments with a very strong connection: the Hadron Production (HARP) experiment located at CERN in Geneva, Switzerland, and the Mini Booster Neutrino Experiment (Mini-BooNE) located at Fermilab in Batavia, Illinois.

Understanding single charged pion production via neutrino-nucleus charged current interaction in the neutrino energy region of a few GeV is essential for future neutrino oscillation experiments since this process is a dominant background for {nu}{sub {mu}} {yields} {nu}{sub x} oscillation measurements. There are two contributions to this process: single pion production via baryonic resonance ({nu}{sub {mu}}N {yields} {mu}{sup -} N{pi}{sup +}) and coherent pion production interacting with the entire nucleus ({nu}{sub {mu}}A {yields} {mu}{sup -} A{pi}{sup +}), where N is nucleon in the nucleus and A is the nucleus. The purpose of the study presented in this thesis is a precise measurement of charged current single charged pion productions, resonant and coherent pion productions, with a good final state separation in the neutrino energy region of a few GeV. In this thesis, we focus on the study of charged current coherent pion production from muon neutrinos scattering on carbon, {nu}{sub {mu}} {sup 12}C {yields} {mu}{sup -12}C{pi}{sup +}, in the SciBooNE experiment. This is motivated by the fact that without measuring this component first, the precise determination of resonant pion production cross section can not be achieved since the contribution of coherent pion production in the region of small muon scattering …

We present a search for standard model Higgs boson production in association with a W boson in proton-antiproton collisions (p{bar p} {yields} W{sup {+-}}H {yields} {ell}{nu}b{bar b}) at a center of mass energy of 1.96 TeV. WH candidate events have a signature of a single lepton (E{sup {+-}}/{mu}{sup {+-}}), missing transverse energy, and two jets. The search looks for candidate events in approximately 2.7 fb{sup -1} of data recorded with the CDF II detector. The high-p{sub T} lepton (e,{mu}) in the events provides a distinct signature for triggering and most of the events in the dataset come from high-p{sub t} lepton triggers. Our analysis improves on prior searches by including events recorded on the E{sub T} + 2 Jets trigger with a lepton reconstructed as an isolated high-p{sub T} charged particle. We increase the sample purity by identifying ('tagging') long-lived b-hadrons in jets. A neural network combines distinguishing kinematic information into a function optimized for WH sensitivity. The neural network output distributions are consistent with the standard model background expectations and we set limits upper limits on the rate of Higgs production. We set 95% confidence level upper limits on the WH production cross section times branching ratio for Higgs …

The author presents a measurement of p{bar p} {yields} Z{gamma} + X {yields} e{sup +}e{sup -}{gamma} + X production using proton-antiproton collisions data collected at the Collider Detector at Fermilab at a center of mass energy of 1.96 TeV. Z{gamma} production provides a direct test of the triple neutral gauge couplings. A measurement of Z{gamma} production cross section and search for anomalous ZZ{gamma} and Z{gamma}{gamma} couplings are presented. The data presented are from 1.1 fb{sup -1} of p{bar p} integrated luminosity collected at the CDF Detector. Electrons from Z decays are selected with E{sub t} > 20 Gev. Photons (E{sub t} > 7 GeV) are required to be well-separated from the electrons. There are 390 ee{gamma} candidate events found with 1.1 fb{sup -1} of data, compared to the SM prediction of 375.3 {+-} 25.2 events. The Standard Model prediction for the cross section for p{bar p} {yields} e{sup +}e{sup -}{gamma} + X production at {radical}s = 1.96 TeV is 4.5 {+-} 0.4 pb. The measured cross section is 4.7 {+-} 0.6 pb. The cross section and kinematic distributions of the ee{gamma} events are in good agreement with theoretical predictions. Limits on the ZZ{gamma} and Z{gamma}{gamma} couplings are extracted using the …

The diphoton differential cross-section as a function of mass up to 300 GeV/c{sup 2}, q{sub T} up to 100 GeV/c, and opening angle over a range of 0 to {pi} radians is measured. The measurement is performed using 1046.19 pb{sup -1} of data collected at Fermi National Accelerator Laboratory using the D0 detector. This analysis considers all direct diphoton states but attempts to suppress contributions due to fragmentation.

We calculate the exclusion region in the parameter space of {nu}{sub {mu}} {yields} {nu}{sub e} oscillations of the LSND type using a combined fit to the reconstructed energy distributions of neutrino candidate samples from the MiniBooNE data obtained with two different particle identification methods. The two {nu}{sub e} candidate samples are included together with a high statistics sample of {nu}{sub {mu}} events in the definition of a {chi}{sup 2} statistic which includes the correlations between the energy intervals of all three samples and handles the event overlap between the {nu}{sub e} samples. The {nu}{sub {mu}} sample is introduced to constrain the effect of systematic uncertainties. This analysis increases the exclusion limit in the region {Delta}m{sup 2} {approx}< 1eV{sup 2} when compared with the result previously published by the collaboration, which used a different technique.

Arsenic in drinking water is a major public health problem threatening the lives of over 140 million people worldwide. In Bangladesh alone, up to 57 million people drink arsenic-laden water from shallow wells. ElectroChemical Arsenic Remediation(ECAR) overcomes many of the obstacles that plague current technologies and can be used affordably and on a small-scale, allowing for rapid dissemination into Bangladesh to address this arsenic crisis. In this work, ECAR was shown to effectively reduce 550 - 580 mu g=L arsenic (including both As[III]and As[V]in a 1:1 ratio) to below the WHO recommended maximum limit of 10 mu g=L in synthetic Bangladesh groundwater containing relevant concentrations of competitive ions such as phosphate, silicate, and bicarbonate. Arsenic removal capacity was found to be approximately constant within certain ranges of current density, but was found to change substantially between ranges. In order of decreasing arsenic removal capacity, the pattern was: 0.02 mA=cm2> 0.07 mA=cm2> 0.30 - 1.1 mA=cm2> 5.0 - 100 mA=cm2. Current processing time was found to effect arsenic removal capacity independent of either charge density or current density. Electrode polarization studies showed no passivation of the electrode in the tested range (up to current density 10 mA=cm2) and ruled out oxygen …

The authors have studied the W + {ge} n jets process in Tevatron Run II experiment. The data used correspond to a total integrated luminosity of 72 pb{sup -1} taken from March 2002 through January 2003. The lowest order QCD predictions have been tested with a new prescription of the parton-jet matching, which allows to construct the enhanced LO phase space. According to this procedure, one gets unique results which do not depend on unphysical bias of kinematical cuts to avoid the collinear/infrared divergence in calculation. Namely, one can get the meaningful results in the lowest order prediction. The controllable event samples of the W boson plus jets events by the enhanced lowest order prediction will lead smaller systematic uncertainty than the naive prediction without any cares of the collinear/infrared divergence. They expect their method will be also useful to make systematically small samples as the background estimates in the top quark analysis. They found a good agreement between data and theory in typical kinematics distributions. The number of events for each inclusive sample up to 3 jets are compared with Monte Carlo calculations. A comparison with Run I results is also presented. This is the first result for the …

Elementary particle physics raises questions that are several thousand years old. What are the fundamental components of matter and how do they interact? These questions are linked to the question of what happened in the very first moments after the creation of the universe. Modern physics systematically tests nature to find answers to these and other fundamental questions. Precise theories are developed that describe various phenomena and at the same time are reduced to a few basic principals of nature. Simplification and reduction have always been guiding concepts of physics. The interplay between experimental data and theoretical descriptions led to the Standard Model of elementary particle physics. It summarizes the laws of nature and is one of most precise descriptions of nature achieved by mankind. Despite the great success of the Standard Model it is not the ultimate theory of everything. Models beyond the Standard Model try to unify all interactions in one grand unified theory. The number of free parameters is attempted to be reduced. Gravity is attempted to be incorporated. Extensions to the Standard Model like supersymmetry address the so-called hierarchy problem. Precision measurements are the key for searches of new particles and new physics. A powerful tool …

The thesis presented here includes two parts. The first part discusses the production of endcap modules for the ATLAS SemiConductor Tracker at the University of Geneva. The ATLAS experiment is one of the two multi-purpose experiments being built at the LHC at CERN. The University of Geneva invested extensive efforts to create an excellent and efficient module production site, in which 655 endcap outer modules were constructed. The complexity and extreme requirements for 10 years of LHC operation with a high resolution, high efficiency, low noise tracking system resulted in an extremely careful, time consuming production and quality assurance of every single module. At design luminosity about 1000 particles will pass through the tracking system each 25 ns. In addition to requiring fast tracking techniques, the high particle flux causes significant radiation damage. Therefore, modules have to be constructed within tight and accurate mechanical and electrical specification. A description of the ATLAS experiment and the ATLAS Semiconductor tracker is presented, followed by a detailed overview of the module production at the University of Geneva. My personal contribution to the endcap module production at the University of Geneva was taking part, together with other physicists, in selecting components to be assembled …

The lifetimes of the B{sup -}, B{sup 0} and B{sub s}{sup 0} mesons are measured using partially reconstructed semileptonic decays. Following semileptonic decay processes and their charge conjugates are used for this analysis: B{sup -}/B{sup 0} {yields} {ell}{sup -}{nu}D{sup 0}X; B{sup -}/B{sup 0} {yields} {ell}{sup -}{nu}D*{sup +}X; B{sub s}{sup 0} {yields} {ell}{sup -}{nu}D{sub s}{sup +}x, where {ell}{sup -} denotes either a muon or electron. The data are collected during 2002-2004 by the 8 GeV single lepton triggers in CDF Run II at the Fermilab Tevatron Collider. Corresponding integrated luminosity is about 260 and 360 pb{sup -1} used for the B{sup -}/B{sup 0} and B{sub s}{sup 0} lifetime analyses, respectively. With the single lepton triggers, events which contain a muon or electron with a transverse momentum greater than 8 GeV/c are selected. For these lepton candidates, further lepton identification cuts are applied to improve purity of the B semileptonic decay signal. After the lepton selection, three types of charm mesons associated with the lepton candidates are reconstructed. Following exclusive decay modes are used for the charm meson reconstruction: D{sup 0} {yields} K{sup -}{pi}{sup +}; D*{sup +} {yields} D{sup 0}{pi}{sub s}{sup +}, followed by D{sup 0} {yields} K{sup -}{pi}{sup +}; D{sub s}{sup …

Evidence from observational cosmology and astrophysics indicates that about one third of the universe is matter, but that the known baryonic matter only contributes to the universe at 4%. A large fraction of the universe is cold and non-baryonic matter, which has important role in the universe structure formation and its evolution. The leading candidate for the non-baryonic dark matter is Weakly Interacting Massive Particles (WIMPs), which naturally occurs in the supersymmetry theory in particle physics. The Cryogenic Dark Matter Search (CDMS) experiment is searching for evidence of a WIMP interaction off an atomic nucleus in crystals of Ge and Si by measuring simultaneously the phonon energy and ionization energy of the interaction in the CDMS detectors. The WIMP interaction energy is from a few keV to tens of keV with a rate less than 0.1 events/kg/day. To reach the goal of WIMP detection, the CDMS experiment has been conducted in the Soudan mine with an active muon veto and multistage passive background shields. The CDMS detectors have a low energy threshold and background rejection capabilities based on ionization yield. However, betas from contamination and other radioactive sources produce surface interactions, which have low ionization yield, comparable to that of …

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.

A radiological dispersion device (RDD) is a device which deliberately releases radioactive material for the purpose of causing terror or harm. In the event that a dirty bomb is detonated, there may be airborne radioactive material that can be inhaled as well as settle on an individuals leading to external contamination.

The Collider Detector at Fermilab (CDF) is a multi-purpose detector designed to study proton-antiproton collisions at center-of-mass energies of 1.96 TeV/c{sup 2}. One of the most importatn components of CDF is the silicon tracking detector. A detailed description of the testing and construction of the CDF silicon tracker is presented. Measurements of the tracking efficiency of the completed detector are also provided. Using 36 pb{sup -1} of the J/{psi} data sample collected by CDF between February and October 2002, the inclusive B {yields} J/{psi} X cross-section is measured in p{bar p} interactions at {radical}s = 1.96 TeV/c{sup 2}. The fraction of J/{psi} events arising from the decay of b hadrons is extracted using an unbinned maximum likelihood fit to the decay length of the J/{psi} candidates. The p{sub T} dependent differential cross section for inclusive B {yields} J/{psi} X events with rapidity |y| < 0.6 is obtained by combining the B-fraction result with a measurement of the J/{psi} differential cross-section. For 2.0 < p{sub T}(J/{psi}) < 17.0 GeV/c, the integrated B {yields} J/{psi} X cross-section is measured to be {sigma}(J/{psi}, B) {center_dot} {Beta}(J/{psi} {yields} {mu}{mu}) = 16.02 {+-} 0.24(stat){sub -2.20}{sup +2.26}(syst) nb.

This dissertation presents a direct measurement of the W boson mass (M{sub W}) and decay width ({Lambda}{sub W}) in 1 fb{sup -1} of W {yields} e{nu} collider data at D0 using a novel method to model the hadronic recoil. The mass is extracted from fits to the transverse mass M{sub T}, p{sub T}(e), and E{sub T} distributions. The width is extracted from fits to the tail of the M{sub T} distribution. The electron energy measurement is simulated using a parameterized model, and the recoil is modeled using a new technique by which Z recoils are chosen from a data library to match the p{sub T} and direction of each generated W boson. We measure the the W boson mass to be M{sub W} = 80.4035 {+-} 0.024(stat) {+-} 0.039(syst) from the M{sub T}, M{sub W} = 80.4165 {+-} 0.027(stat) {+-} 0.038(syst) from the pT(e), and MW = 80.4025 {+-} 0.023(stat) {+-} 0.043(syst) from the E{sub T} distributions. {Lambda}{sub W} is measured to be {Lambda}{sub W} = 2.025 {+-} 0.038(stat) {+-} 0.061(syst) GeV.

I present an analysis of b{bar b} pair production correlations, using dimuon-triggered data collected with the Collider Detector at Fermilab (CDF) in p{bar p} collisions at {radical}s = 1.96 TeV during Run II of the TeVatron. The leading order (LO) and next-to-leading order (NLO) b quark production processes are discriminated by the angular and momentum correlations between the b{bar b} pair. Track-level jets containing a muon are classified by b quark content and used to estimate the momentum vector of the progenitor b quark. The theoretical distributions given by the MC{at}NLO event generator are tested against the data.

This research is divided into two related topics. In the first topic, the synthesis and characterization of novel composite materials reinforced with MWCNTs by ring-opening metathesis polymerization (ROMP) is reported for two ROMP based monomers: dicyclopentadiene (DCPD) and 5-ethylidene-2-norbornene (ENB). Homogeneous dispersion of MWCNTs in the polymer matrices is achieved by grafting norbornene moieties onto the nanotube surface. For the DCPD-based system, the investigation of mechanical properties of the composites shows a remarkable increase of tensile toughness with just 0.4 wt % of functionalized MWCNTs (f-MWCNTs). To our knowledge, this represents the highest toughness enhancement efficiency in thermosetting composites ever reported. DMA results show that there is a general increase of thermal stability (rg) with the addition of f-MWCNTs, which means that covalently bonded f-MWCNTs can reduce the local chain mobility of the matrix by interfacial interactions. The ENB system also shows significant enhancement of the toughness using just 0.8 wt % f-MWCNTs. These results indicate that the ROMP approach for polyENB is also very effective. The second topic is an investigation of the biorenewable rubbers synthesized by the tandem ROMP and cationic polymerization. The resin consists of a norbornenyl-modified linseed oil and a norbornene diester. Characterization of the bio-based …

This is a doctoral dissertation, in French, on the subject of study, design and realization of a Fabry-Perot cavity for the Compton polarimeter of TJNAF.

We report a measurement of the mass of the top quark (m{sub top}) in p{bar p} collisions at a center of mass energy of 1.96 TeV. The analysis is based on p{bar p}{yields}t{bar t}{yields} lepton+jets data recorded with the D0 detector at the Fermilab Tevatron Collider. Events were preselected in the e+jets (913 events/pb of data) and in the {mu}+jets (871 events/pb of data) channels. These were analyzed through a comparison of the matrix element for the production and decay of the t{bar t} states with data, using a likelihood method and 'tagged' b quarks from the t {yields} Wb decays.

Fermilab Experiment 866 took single muon data from 800 GeV/c ({radical}s = 38.8 GeV) p-Cu and p-Be interactions in an attempt to extract the inclusive nuclear open charm/anti-charm (D/{bar D}) differential cross sections as a function of p{sub T}. The muons were decay products from semi-leptonic decays of open charm mesons as well as decays from lighter non-charmed mesons ({pi}'s and K's). Data were taken simultaneously from two interaction regions; one of two thin nuclear targets and a copper beam dump 92 inches downstream. The open decay length for hadrons produced in the targets increased the contribution to the muon spectrum from light hadron decays, relative to those from the dump. Production cross sections for light hadrons from previous experiments were used in conjunction with parameterized open charm cross sections to produce total Monte Carlo single muon spectra that were subsequently fit to the data. The sensitivity of this measurement covered an open charm hadron p{sub T} range of approximately 2 to 7 GeV/c, center-of-mass rapidity, y{sub cm}, between 0 and 2, and x{sub F} between 0.2 and 0.8. Previous experimental results for p-p or p-A open charm production at comparable energy was limited to {radical}5 GeV/ Three functions describing …

This thesis describes the first search for electroweak single top quark production in proton-antiproton collisions at a center of mass energy of 1.96 TeV. The data sample used for this analysis corresponds to 162 pb{sup -1} recorded by the upgraded Collider Detector at Fermilab. The search is performed by doing a classic maximum likelihood fit to the H{sub T} distribution in data. The kinematic variable H{sub T} is the scalar sum of transverse energies of all final state particles in the event. This variable has the advantage that its distribution looks very similar for both contributing (s-channel and t-channel) single top processes, but is different for background processes. The combination of both channels to one signal improves the sensitivity of the search. No significant evidence for electroweak single top quark production is found and we set an upper limit at the 95% confidence level on the combined single top quark production cross section of 17.8 pb.

The authors present a measurement of the {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +} {pi}{sup -} branching ratio in p{bar p} collisions at {radical}s = 1.96 TeV using 65 pb{sup -1} data collected by the Collider Detector at Fermilab (CDF). The measurement starts from reconstructing two decay modes: {Lambda}{sub b}{sup 0} {yields} {Lambda}{sub c}{sup +}{pi}{sup -}, where {Lambda}{sub c}{sup +} {yields} p K{sup -} {pi}{sup +}; and {bar B}{sup 0} {yields} D{sup +}{pi}{sup -}, where D{sup +} {yields} {pi}{sup +} K{sup -} {pi}{sup +}. The authors obtained 96 {+-} 13 {Lambda}{sub b}{sup 0} and 321 {+-} 22 {bar B}{sup 0} candidates from the CDF Run II Two-Track Hadronic Trigger data sample. The relative branching ratio of the two decays is then measured based on the equation: f{sub {Lambda}{sub b}} BR({Lambda}{sub b} {yields} {Lambda}{sub c}{sup +} {pi}{sup -})/f{sub d} BR({bar B}{sup 0} {yields} D{sup +} {pi}{sup -}) = BR(D{sup +} {yields} K{pi}{pi}) N{sub {Lambda}{sub b}} {epsilon}{sub B{sup 0}}/BR({Lambda}{sub c}{sup +} {yields} pK{pi}) N{sub {bar B}{sup 0}} {epsilon}{sub {Lambda}{sub b}}. The measurement gives f{sub {Lambda}{sub b}} BR({Lambda}{sub b} {yields} {Lambda}{sub c}{sup +}{pi}{sup -})/f{sub d} BR({bar B}{sup 0} {yields} D{sup +}{pi}{sup -}) = 0.66 {+-} 0.11(stat) {+-} 0.09(syst) {+-} 0.18(BR). The {Lambda}{sub b}{sup …