What constitutes the spin of the nucleon? The answer to this question is still not completely understood. Although we know the longitudinal quark spin content very well, the data on the transverse quark spin content of the nucleon is still very sparse. Semi-inclusive Deep Inelastic Scattering (SIDIS) using transversely polarized targets provide crucial information on this aspect. The data that is currently available was taken with proton and deuteron targets. The E06-010 experiment was performed at Jefferson Lab in Hall-A to measure the single spin asymmetries in the SIDIS reaction n↑(e, e′π{sup ±}/K{sup ±})X using transversely polarized {sup 3}He target. The experiment used the continuous electron beam provided by the CEBAF accelerator with a beam energy of 5.9 GeV. Hadrons were detected in a high-resolution spectrometer in coincidence with the scattered electrons detected by the BigBite spectrometer. The kinematic coverage focuses on the valence quark region, x = 0.19 to 0.34, at Q{sup 2} = 1.77 to 2.73 (GeV/c){sup 2}. This is the first measurement on a neutron target. The data from this experiment, when combined with the world data on the proton and the deuteron, will provide constraints on the transversity and Sivers distribution functions on both the u …

The Standard Model describes with a very good accuracy all interactions of the, so far, known elementary particles. However the Higgs mechanism, which gives rise to the observed mass of these particles, has not yet been confirmed. The Higgs particle has not yet been observed, and the observation or exclusion is an important test of the Standard Model. The Standard Model does not predict the mass of the Higgs particle, however it does impose some limits on the range in which this mass can lie. In direct searches a Higgs with a mass smaller than 114.4 GeV and within 162 GeV and 166 GeV has been excluded at 95% CL at the LEP and the Tevatron colliders. The analysis presented in this thesis is aimed to search for the ZH → μμb$\bar{b}$ events in 3.1 fb^-1 of data collected with the DØ detector in p$\bar{p}$ collisions at √s = 1.96 TeV.

Elucidating the nature of neutrino oscillation continues to be a goal in the vanguard of the efforts of physics experiment. As neutrino oscillation searches seek an increasingly elusive signal, a thorough understanding of the possible backgrounds becomes ever more important. Measurements of neutrino-nucleus interaction cross sections are key to this understanding. Searches for {nu}{sub {mu}} {yields} {nu}{sub e} oscillation - a channel that may yield insight into the vanishingly small mixing parameter {theta}{sub 13}, CP violation, and the neutrino mass hierarchy - are particularly susceptible to contamination from neutral current single {pi}{sup 0} (NC 1{pi}{sup 0}) production. Unfortunately, the available data concerning NC 1{pi}{sup 0} production are limited in scope and statistics. Without satisfactory constraints, theoretical models of NC 1{pi}{sup 0} production yield substantially differing predictions in the critical E{sub {nu}} {approx} 1 GeV regime. Additional investigation of this interaction can ameliorate the current deficiencies. The Mini Booster Neutrino Experiment (MiniBooNE) is a short-baseline neutrino oscillation search operating at the Fermi National Accelerator Laboratory (Fermilab). While the oscillation search is the principal charge of the MiniBooNE collaboration, the extensive data ({approx} 10{sup 6} neutrino events) offer a rich resource with which to conduct neutrino cross section measurements. This work concerns …

This thesis presents the measurement of the charged current quasi-elastic (CCQE) neutrino-nucleon cross section at neutrino energies around 1 GeV. This measurement has two main physical motivations. On one hand, the neutrino-nucleon interactions at few GeV is a region where existing old data are sparse and with low statistics. The current measurement populates low energy regions with higher statistics and precision than previous experiments. On the other hand, the CCQE interaction is the most useful interaction in neutrino oscillation experiments. The CCQE channel is used to measure the initial and final neutrino fluxes in order to determine the neutrino fraction that disappeared. The neutrino oscillation experiments work at low neutrino energies, so precise measurement of CCQE interactions are essential for flux measurements. The main goal of this thesis is to measure the CCQE absolute neutrino cross section from the SciBooNE data. The SciBar Booster Neutrino Experiment (SciBooNE) is a neutrino and anti-neutrino scattering off experiment. The neutrino energy spectrum works at energies around 1 GeV. SciBooNE was running from June 8th 2007 to August 18th 2008. In that period, the experiment collected a total of 2.65 x 10²⁰ protons on target (POT). This thesis has used full data collection in …

The MINOS experiment was designed to measure neutrino oscillation parameters with muon neutrinos. It achieves this by measuring the neutrino energy spectrum and flavor composition of the man-made NuMI neutrino beam 1km after the beam is formed and again after 735 km. By comparing the two spectra it is possible to measure the oscillation parameters. The NuMI beam is made up of 7.0%$\bar{v}$_μ, which can be separated from the v_μ because the MINOS detectors are magnetized. This makes it possible to study $\bar{v}$_μ oscillations separately from those of muon neutrinos, and thereby test CPT invariance in the neutrino sector by determining the $\bar{v}$_μ oscillation parameters and comparing them with those for v_μ, although any unknown physics of the antineutrino would appear as a difference in oscillation parameters. Such a test has not been performed with beam $\bar{v}$_μ before. It is also possible to produce an almost pure $\bar{v}$_μ beam by reversing the current through the magnetic focusing horns of the NuMI beamline, thereby focusing negatively, instead of positively charged particles. This thesis describes the analysis of the 7% $\bar{v}$_μ component of the forward horn current NuMI beam. The $\bar{v}$_μ of a data sample of 3.2 x 10{sup 20} protons on …

We present a search for associated production of Z and Higgs bosons in 4.2 fb{sup -1} of {bar p}p collisions at {radical}s = 1.96 TeV, produced in RunII of the Tevatron and recorded by the D0 detector. The search is performed in events containing at least two muons and at least two jets. The ZH signal is distinguished from the expected backgrounds by means of multivariate classifiers known as random forests. Binned random forest output distributions are used in comparing the data to background-only and signal+background hypotheses. No excess is observed in the data, so we set upper limits on ZH production with a 95% confidence level.

Gamma ray detectors are important in national security applications, medicine, and astronomy. Semiconductor materials with high density and atomic number, such as Cadmium Telluride (CdTe), offer a small device footprint, but their performance is limited by noise at room temperature; however, improved device design can decrease detector noise by reducing leakage current. This thesis characterizes and models two unique Schottky devices: one with an argon ion sputter etch before Schottky contact deposition and one without. Analysis of current versus voltage characteristics shows that thermionic emission alone does not describe these devices. This analysis points to reverse bias generation current or leakage through an inhomogeneous barrier. Modeling the devices in reverse bias with thermionic field emission and a leaky Schottky barrier yields good agreement with measurements. Also numerical modeling with a finite-element physics-based simulator suggests that reverse bias current is a combination of thermionic emission and generation. This thesis proposes further experiments to determine the correct model for reverse bias conduction. Understanding conduction mechanisms in these devices will help develop more reproducible contacts, reduce leakage current, and ultimately improve detector performance.

At a hadron collider, diphoton (γγ) production allows detailed studies of the Standard Model (SM), as well as as searches for new phenomena, such as new heavy resonances, extra spatial dimensions or cascade decays of heavy new particles. Within the SM, continuum γγ+X production is characterized by a steeply-falling γγ mass spectrum, on top of which a heavy resonance decaying into γγ can potentially be observed. In particular, this is considered one of the most promising discovery channels for a SM Higgs boson at the LHC, despite the small branching ratio of BR (H → γγ) {approx} 0.2% for 110 < M_Higgs < 140 GeV. At the Tevatron, the dominant SM Higgs boson production mechanism is gluon fusion, followed by associated production with a W or Z boson, and vector boson fusion. While the SM Higgs production rate at the Tevatron is not sufficient to observe it in the γγ mode, the Hgg and Hγγ couplings, being loop-mediated, are particularly sensitive to new physics effects. Furthermore, in some models beyond the SM, for instance, fermiophobic Higgs, with no couplings to fermions, the BR (H → γγ) can be enhanced significantly relative to the SM prediction, while has the SM-like production …

High Pressure Scanning Tunneling Microscopy (HP-STM) and Ambient Pressure X-ray Photoelectron Spectroscopy were used to study the structural properties and catalytic behavior of noble metal surfaces at high pressure. HP-STM was used to study the structural rearrangement of the top most atomic surface layer of the metal surfaces in response to changes in gas pressure and reactive conditions. AP-XPS was applied to single crystal and nanoparticle systems to monitor changes in the chemical composition of the surface layer in response to changing gas conditions. STM studies on the Pt(100) crystal face showed the lifting of the Pt(100)-hex surface reconstruction in the presence of CO, H₂, and Benzene. The gas adsorption and subsequent charge transfer relieves the surface strain caused by the low coordination number of the (100) surface atoms allowing the formation of a (1 x 1) surface structure commensurate with the bulk terminated crystal structure. The surface phase change causes a transformation of the surface layer from hexagonal packing geometry to a four-fold symmetric surface which is rich in atomic defects. Lifting the hex reconstruction at room temperature resulted in a surface structure decorated with 2-3 nm Pt adatom islands with a high density of step edge sites. Annealing …

General introduction to OLED basics and OLED-based structurally integrated sensors was provided in chapter 1 and chapter 2. As discussed in chapter 3, OLEDs were developed or improved using novel engineering methods for better charge injection (increased by over 1 order of magnitude) and efficiency. As the excitation sources, these OLEDs have preferred characteristics for sensor applications, including narrowed emission, emission at desired wavelength, and enhanced output for reduced EL background, higher absorption and improved device lifetime. In addition to OLEDs with desired performance, sensor integration requires oxidase immobilization with the sensor film for O₂-based biological and chemical sensing. Nanoparticles such as ZnO have large surface area and high isoelectric point (~9.5), which favors enzyme immobilization via physical adsorption as well as Coulombic bonding. In chapter 4, it was demonstrated that ZnO could be used for this purpose, although future work is needed to further bond the ZnO to the sensor film. In chapter 5, single unit sensor was extended to multianalyte parallel sensing based on an OLED platform, which is compact and integrated with silicon photodiodes and electronics. Lactate and glucose were simultaneously monitored with a low limit of detection 0.02 mM, fast response time (~1 minute) and dynamic …

The organization of this thesis consists of three main ideas: the first presents the theoretical framework and experimental, as well as objects used in the analysis and the second relates to the various work tasks of service that I performed on the calorimeter, and the third is the search for the Higgs boson in the channel ZH → e⁺e^-b$\bar{b}$. Thus, this thesis has the following structure: Chapter 1 is an introduction to the standard model of particle physics and the Higgs mechanism; Chapter 2 is an overview of the complex and the acceleration of the Tevatron at Fermilab DØ detector; Chapter 3 is an introduction to physical objects used in this thesis; Chapter 4 presents the study made on correcting the energy measured in the calorimeter; Chapter 5 describes the study of certification of electrons in the calorimeter; Chapter 6 describes the study of certification of electrons in the intercryostat region of calorimeter; Chapter 7 Detailed analysis on the search for Higgs production in the channel ZH → e⁺e^-b$\bar{b}$; and Chapter 8 presents the final results of the calculations of upper limits to the production cross section of the Higgs boson on a range of low masses.

The Standard Model of particle physics provides an excellent description of particle interactions at energies up to {approx}1 TeV, but it is expected to fail above that scale. Multiple models developed to describe phenomena above the TeV scale predict the existence of very massive, vector-like quarks. A search for single electroweak production of such particles in p{anti p} collisions at a center-of-mass energy of 1.96 TeV is performed in the W+jets and Z+jets channels. The data were collected by the D0 detector at the Fermilab Tevatron Collider and correspond to an integrated luminosity of 5.4 fb{sup -1}. Events consistent with a heavy object decaying to a vector boson and a jet are selected. We observe no significant excess in comparison to the background prediction and set 95% confidence level upper limits on production cross sections for vector-like quarks decaying to W+jet and Z+jet. Assuming a vector-like quark -- standard model quark coupling parameter {tilde {kappa}}{sub qQ} of unity, we exclude vector-like quarks with mass below 693 GeV for decays to W+jet and mass below 449 GeV for decays to Z+jet. These represent the most sensitive limits to date.

We present the measurement of the WW and WZ production cross section in p{bar p} collisions at {radical}s = 1.96 TeV, in a final state consisting of an electron or muon, neutrino and jets. The data analyzed were collected by the CDF II detector at the Tevatron collider and correspond to 4.3 fb{sup -1} of integrated luminosity. The analysis uses a fit to the dijet mass distribution to extract the diboson contribution. We observe 1582 {+-} 275(stat.) {+-} 107(syst.) diboson candidate events and measure a cross section of {sigma}{sub WW/WZ} = 18.1 {+-} 3.3(stat.) {+-} 2.5(syst.) pb, consistent with the Standard Model prediction of 15.9 {+-} 0.9 pb. The best fit to the dijet mass of the known components shows a good agreement with the data except for the [120, 160] GeV/c{sup 2} mass range, where an excess is observed. We perform detailed checks of our background model and study the significance of the excess, assuming an additional gaussian component with a width compatible with the expected dijet mass resolution. A standard {Delta}{sub {chi}}{sup 2} test of the presence of the additional component, returns a p-value of 4.2 x 10{sup -4} when standard sources of systematics are considered, corresponding to …

The Standard Model (SM) is one of the most tested and verified physical theories of all time, present experimental observations are consistent with SM expectations. On the other hand SM can not explain many physical observations: the cosmological observations possibly infer the presence of dark matter which is clearly beyond the SM expectations; the SM Higgs model, while explaining the generation of fermion masses, can not explain the hierarchy problem and a non natural fine tuning of SM is needed to cancel out quadratic divergences in the Higgs boson mass. New physics (NP) beyond SM should hence be investigated: rising the energy above NP processes thresholds, and detecting new particles or new effects not predicted by the standard model directly, is one of the possible approaches; another approach is to make precision measurements of well known processes or looking for rare processes which involve higher order contribution from NP processes, this approach need higher luminosities with respect to the previous approach but lower beam energies. Search for Lepton Flavor Violation (LFV) in charged lepton decays is promising: neutrino physics provides indeed a clear and unambiguous evidence of LFV in the neutral lepton sector via mixing processes, which have been observed …

This Thesis presents measurements of the decays B{sup -} {yields} {Xi}{sub c}{sup 0}{bar {Lambda}}{sub c}{sup -}, {bar B}{sup 0} {yields} {Xi}{sub c}{sup +}{bar {Lambda}}{sub c}{sup -}, B{sup -} {yields} {Lambda}{sub c}{sup +}{bar {Lambda}}{sub c}{sup -} K{sup -}, and {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +}{bar {Lambda}}{sub c}{sup -} K{sub s}{sup 0} based on 228 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory.

The work in this dissertation presents the synthesis of two mixed metal oxides for biofuel applications and NMR characterization of silica materials. In the chapter 2, high catalytic efficiency of calcium silicate is synthesized for transesterfication of soybean oil to biodisels. Chapter 3 describes the synthesis of a new Rh based catalyst on mesoporous manganese oxides. The new catalyst is found to have higher activity and selectivity towards ethanol. Chapter 4 demonstrates the applications of solid-state Si NMR in the silica materials.

The production of single, highly forward {pi}{sup 0} mesons by NC coherent neutrino-nucleus interactions ({nu}{sub {mu}} + N {yields} {nu}{sub {mu}} + N + {pi}{sup 0}) is a process which probes fundamental aspects of the weak interaction. This reaction may also pose as a limiting background for long baseline searches for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations if the neutrino mixing angle {theta}{sub 13} is very small. The high-statistics sample of neutrino interactions recorded by the MINOS Near Detector provides an opportunity to measure the cross section of this coherent reaction on a relatively large-A nucleus at an average E{sub {nu}} = 4.9 GeV. A major challenge for this measurement is the isolation of forward-going electromagnetic (EM) showers produced by the relatively rare coherent NC({pi}{sup 0}) process amidst an abundant rate of incoherently produced EM showers. The backgrounds arise from single {pi}{sup 0} dominated NC events and also from quasi-elastic-like CC scattering of electron neutrinos. In this Thesis the theory of coherent interactions is summarized, and previous measurements of the coherent NC({pi}{sup 0}) cross section are reviewed. Then, methods for selecting a sample of coherent NC({pi}{sup 0}) like events, extracting the coherent NC({pi}{sup 0}) event rate from that sample, estimating …

The top quark has been discovered by CDF and D0 experiments in 1995 at the proton-antiproton collider Tevatron. The amount of data recorded by both experiments makes it possible to accurately study the properties of this quark: its mass is now known to better than 1% accuracy. This thesis describes the measurement of the top pair cross section in the electron muon channel with 4, 3 fb^-1 recorded data between 2006 and 2009 by the D0 experiment. Since the final state included a muon, improvements of some aspects of its identification have been performed : a study of the contamination of the cosmic muons and a study of the quality of the muon tracks. The cross section measurement is in good agreement with the theoretical calculations and the other experimental measurements. This measurement has been used to extract a value for the top quark mass. This method allows for the extraction of a better defined top mass than direct measurements as it depends less on Monte Carlo simulations. The uncertainty on this extracted mass, dominated by the experimental one, is however larger than for direct measurements. In order to decrease this uncertainty, the ratio of the Z boson and …

A search for dijet resonance production in a four-jet all-hadronic final state from the D0 detector at Fermilab's Tevatron is presented. The data set, acquired at a p{bar p} center-of-mass energy of {radical}s = 1.96 TeV, contains primarily multijet events and represents approximately 1 fb{sup -1} of data. The cross section limits for associated Higgs production and Technicolor processes are determined through a background subtraction method using data to estimate the background. This four-jet channel is potentially very powerful, but is extremely challenging due to the large multijet background from QCD processes. Background rejection is performed by utilizing b-tagging, pre-selection cuts, a multi-variate boosted decision tree discriminant, and the correlated information contained in the M(bb) and M(jj) dijet invariant masses. The search for V H (WH+ZH) processes yields a 95% confidence level observed upper limit of 20.4 pb on the VH cross section for a Higgs mass of 115 GeV/c{sup 2}. Additionally, a 95% confidence level observed upper limit of 16.7 pb was set for a Higgs boson mass of 125 GeV/c{sup 2} and 24.6 pb was set for a Higgs boson mass of 135 GeV/c{sup 2}. The same data set was used to place limits on the Technicolor process …

A search for diphoton events with large missing transverse energy produced in p{bar p} collisions at {radical}s = 1.96 TeV is presented. The data were collected with the D0 detector at the Fermilab Tevatron Collider between 2002 and 2010, and correspond to 6.3 fb{sup -1} of integrated luminosity. The observed missing transverse energy distribution is well described by the Standard Model prediction, and 95% C.L. limits are derived on two realizations of theories beyond the Standard Model. In a gauge mediated supersymmetry breaking scenario, the breaking scale {Lambda} is excluded for {Lambda} < 124 TeV. In a universal extra dimension model including gravitational decays, the compactification radius R{sub c} is excluded for R{sub c}{sup -1} < 477 GeV.

The authors present a search for the decay B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}} ({ell} = {tau}, {mu}, or e) in (458.9 {+-} 5.1) x 10{sup 6} {Upsilon}(4S) decays recorded with the BABAR detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay (B{sup -} {yields} D{sup 0}{ell}{sup -}{bar {nu}}X) is selected, and in the recoil a search for B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}} signal is performed. The {tau} is identified in the following channels: {tau}{sup +} {yields} e{sup +}{nu}{sub e}{bar {nu}}{sub {tau}}, {tau}{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}{bar {nu}}{sub {tau}}, {tau}{sup +} {yields} {pi}{sup +}{bar {nu}}{sub {tau}}, and {tau}{sup +} {yields} {pi}{sup +}{pi}{sup 0}{bar {nu}}{sub {tau}}. The analysis strategy and the statistical procedure is set up for branching fraction extraction or upper limit determination. They determine from the dataset a preliminary measurement of {Beta}(B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}}) = (1.8 {+-} 0.8 {+-} 0.1) x 10{sup -4}, which excludes zero at 2.4{sigma}, and f{sub B} = 255 {+-} 58 MeV. Combination with the hadronically tagged measurement yields {Beta}(B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}}) = (1.8 {+-} 0.6) x 10{sup -4}. They also set preliminary limits on the branching fractions at …

Oxide compounds containing the transition metal vanadium (V) have attracted a lot of attention in the field of condensed matter physics owing to their exhibition of interesting properties including metal-insulator transitons, structural transitions, ferromagnetic and an- tiferromagnetic orderings, and heavy fermion behavior. Binary vanadium oxides VnO_2n-1 where 2 ≤ n ≤ 9 have triclinic structures and exhibit metal-insulator and antiferromagnetic transitions.[1–6] The only exception is V₇O₁₃ which remains metallic down to 4 K.[7] The ternary vanadium oxide LiV₂O₄ has the normal spinel structure, is metallic, does not un- dergo magnetic ordering and exhibits heavy fermion behavior below 10 K.[8] CaV₂O₄ has an orthorhombic structure[9, 10] with the vanadium spins forming zigzag chains and has been suggested to be a model system to study the gapless chiral phase.[11, 12] These provide great motivation for further investigation of some known vanadium compounds as well as to ex- plore new vanadium compounds in search of new physics. This thesis consists, in part, of experimental studies involving sample preparation and magnetic, transport, thermal, and x- ray measurements on some strongly correlated eletron systems containing the transition metal vanadium. The compounds studied are LiV₂O₄, YV₄O₈, and YbV₄O₈. The recent discovery of superconductivity in RFeAsO_1-xF_x (R …

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This thesis reports on two searches for the production of squarks and gluinos, supersymmetric partners of the Standard Model (SM) quarks and gluons, using the CDF detector at the Tevatron √s = 1.96 TeV p$\bar{p}$ collider. An inclusive search for squarks and gluinos pair production is performed in events with large E_T and multiple jets in the final state, based on 2 fb^-1 of CDF Run II data. The analysis is performed within the framework of minimal supergravity (mSUGRA) and assumes R-parity conservation where sparticles are produced in pairs. The expected signal is characterized by the production of multiple jets of hadrons from the cascade decays of squarks and gluinos and large missing transverse energy E_T from the lightest supersymmetric particles (LSP). The measurements are in good agreement with SM predictions for backgrounds. The results are translated into 95% confidence level (CL) upper limits on production cross sections and squark and gluino masses in a given mSUGRA scenario. An upper limit on the production cross section is placed in the range between 1 pb and 0.1 pb, depending on the gluino and squark masses considered. The result of the search is negative for gluino and squark masses up to 392 …