A measurement of the mass of the top quark is presented, using top-antitop pair (t{bar t}) candidate events for the lepton+jets decay channel. The measurement makes use of Tevatron p{bar p} collision data at centre-of-mass energy {radical}s = 1.96 TeV, collected at the CDF detector. The top quark mass is measured by employing an unbinned maximum likelihood method where the event probability density functions are calculated using signal (t{bar t}) and background (W+jets) matrix elements, as well as a set of parameterised jet-to-parton mapping functions. The likelihood function is maximised with respect to the top quark mass, the fraction of signal events, and a correction to the jet energy scale (JES) of the calorimeter jets. The simultaneous measurement of the JES correction ({Delta}{sub JES}) provides an in situ jet energy calibration based on the known mass of the hadronically decaying W boson. Using 578 lepton+jets candidate events corresponding to 3.2 fb{sup -1} of integrated luminosity, the top quark mass is measured to be m{sub t} = 172.4 {+-} 1.4 (stat+{Delta}{sub JES}) {+-} 1.3 (syst) GeV=c{sup 2}, one of the most precise single measurements to date.

The measurement of the WW + WZ production cross section in a semileptonic decay mode is presented. The measurement is carried out with 4.6 fb{sup -1} of integrated luminosity collected by the CDF II detector in {radical}s = 1.96 TeV proton-antiproton collisions at the Tevatron. The main experimental challenge is identifying the signal in the overwhelming background from W+jets production. The modeling of the W+jets background is carefully studied and a matrix element technique is used to build a discriminant to separate signal and background. The cross section of WW + WZ production is measured to be {sigma}(p{bar p} {yields} WW + WZ) = 16.5{sub -3.0}{sup +3.3} pb, in agreement with the next-to-leading order theoretical prediction of 15.1 {+-} 0.9 pb. The significance of the signal is evaluated to be 5.4{sigma}. This measurement is an important milestone in the search for the Standard Model Higgs boson at the Tevatron.

The top quark produced through the electroweak channel provides a direct measurement of the V{sub tb} element in the CKM matrix which can be viewed as a transition rate of a top quark to a bottom quark. This production channel of top quark is also sensitive to different theories beyond the Standard Model such as heavy charged gauged bosons termed W{prime}. This thesis measures the cross section of the electroweak produced top quark using a technique based on using the matrix elements of the processes under consideration. The technique is applied to 2.3 fb{sup -1} of data from the D0 detector. From a comparison of the matrix element discriminants between data and the signal and background model using Bayesian statistics, we measure the cross section of the top quark produced through the electroweak mechanism {sigma}(p{bar p} {yields} tb + X, tqb + X) = 4.30{sub -1.20}{sup +0.98} pb. The measured result corresponds to a 4.9{sigma} Gaussian-equivalent significance. By combining this analysis with other analyses based on the Bayesian Neural Network (BNN) and Boosted Decision Tree (BDT) method, the measured cross section is 3.94 {+-} 0.88 pb with a significance of 5.0{sigma}, resulting in the discovery of electroweak produced top quarks. …

One of the central questions arising from human curiosity has always been what matter is ultimately made of, with the idea of some kind of elementary building-block dating back to the ancient greek philosophers. Scientific activities of multiple generations have contributed to the current best knowledge about this question, the Standard Model of particle physics. According to it, the world around us is composed of a small number of stable elementary particles: Electrons and two different kinds of quarks, called up and down quarks. Quarks are never observed as free particles, but only as bound states of a quark-antiquark pair (mesons) or of three quarks (baryons), summarized as hadrons. Protons and Neutrons, the constituents forming the nuclei of all chemical elements, are baryons made of up and down quarks. The electron and the electron neutrino - a nearly massless particle without electric charge - belong to a group called leptons. These two quarks and two leptons represent the first generation of elementary particles. There are two other generations of particles, which seem to have similar properties as the first generation except for higher masses, so there are six quarks and six leptons altogether. They were around in large amounts shortly …

This work presents the first comprehensive measurement of neutrino-induced charged-current neutral pion production (CC{pi}{sup 0}) off a nuclear target. The Mini Booster Neutrino Experiment (MiniBooNE) and Booster Neutrino Beam (BNB) are discussed in detail. MiniBooNE is a high-statistics ({approx} 1,000,000 interactions) low-energy (E{sub {nu}} {element_of} 0.5-2.0 GeV) neutrino experiment located at Fermilab. The method for selecting and reconstructing CC{pi}{sup 0} events is presented. The {pi}{sup 0} and {mu}{sup -} are fully reconstructed in the final state allowing for the measurement of, among other things, the neutrino energy. The total observable CC{pi}{sup 0} cross-section is presented as a function of neutrino energy, along with five differential cross-sections in terms of the final state kinematics and Q{sup 2}. The results are combined to yield a flux-averaged total cross-section of <{sigma}>{sub {Phi}} = (9.2 {+-} 0.3{sub stat.} {+-} 1.5{sub syst}.) x 10{sup -39} cm{sup 2}/CH{sub 2} at energy 965 MeV. These measurements will aid future neutrino experiments with the prediction of their neutrino interaction rates.

The primary goals of the BABAR experiment are the detection of CP violation (CPV) in the B meson system, the precise measurement of some of the elements of the CKM matrix and the measurement of the rates of rare B meson decays. At present, BABAR has achieved major successes: (1) the discovery, in neutral B decays, of direct and mixing-induced CP violation; (2) accurate measurements of the magnitudes of the CKM matrix elements |V{sub cb}| and |V{sub ub}|; (3) a precise measurement of the CKM parameter {beta} {triple_bond} arg[- V{sub cd}V*{sub cb}/V{sub td}V*{sub tb}]; (4) a first measurement of the CKM parameters {alpha} {triple_bond} arg[- V{sub td}V*{sub tb}/V{sub ud}V*{sub ub}], {gamma} {triple_bond} arg[- V{sub ud}V*{sub ub}/V{sub cd}V*{sub cb}]; and (5) the observation of several rare B decays and the discovery of new particles (in the charmed and charmonium mesons spectroscopy). However, the physics program of BABAR is not yet complete. Two of the key elements of this program that still need to be achieved are: (1) the observation of direct CP violation in charged B decays, which would constitute the first evidence of direct CPV in a charged meson decay; and (2) the precise measurement of {alpha} and {gamma}, which …

Many modern scientific applications rely on highly computation intensive calculations. However, most applications do not concentrate as much on the role that input/output operations can play for improved performance and portability. Parallelizing input/output operations of large files can significantly improve the performance of parallel applications where sequential I/O is a bottleneck. A proper choice of I/O library also offers a scope for making input/output operations portable across different architectures. Thus, use of parallel I/O libraries for organizing I/O of large data files offers great scope in improving performance and portability of applications. In particular, sequential I/O has been identified as a bottleneck for the highly scalable MFDn (Many Fermion Dynamics for nuclear structure) code performing ab-initio nuclear structure calculations. We develop interfaces and parallel I/O procedures to use a well-known parallel I/O library in MFDn. As a result, we gain efficient I/O of large datasets along with their portability and ease of use in the down-stream processing. Even situations where the amount of data to be written is not huge, proper use of input/output operations can boost the performance of scientific applications. Application checkpointing offers enormous performance improvement and flexibility by doing a negligible amount of I/O to disk. Checkpointing …

Metallic glasses have been a promising class of materials since their discovery in the 1960s. Indeed, remarkable chemical, mechanical and physical properties have attracted considerable attention, and several excellent reviews are available. Moreover, the special group of glass forming alloys known as the bulk metallic glasses (BMG) become amorphous solids even at relatively low cooling rates, allowing them to be cast in large cross sections, opening the scope of potential applications to include bulk forms and net shape structural applications. Recent studies have been reported for new bulk metallic glasses produced with lower cooling rates, from 0.1 to several hundred K/s. Some of the application products of BMGs include sporting goods, high performance springs and medical devices. Several rapid solidification techniques, including melt-spinning, atomization and surface melting have been developed to produce amorphous alloys. The aim of all these methods is to solidify the liquid phase rapidly enough to suppress the nucleation and growth of crystalline phases. Furthermore, the production of amorphous/crystalline composite (ACC) materials by partial crystallization of amorphous precursor has recently given rise to materials that provide better mechanical and magnetic properties than the monolithic amorphous or crystalline alloys. In addition, these advances illustrate the broad untapped potential …

Trust management techniques must be adapted to the unique needs of the application architectures and problem domains to which they are applied. For autonomic computing systems that utilize mobile agents and ant colony algorithms for their sensor layer, certain characteristics of the mobile agent ant swarm -- their lightweight, ephemeral nature and indirect communication -- make this adaptation especially challenging. This thesis looks at the trust issues and opportunities in swarm-based autonomic computing systems and finds that by monitoring the trustworthiness of the autonomic managers rather than the swarming sensors, the trust management problem becomes much more scalable and still serves to protect the swarm. After analyzing the applicability of trust management research as it has been applied to architectures with similar characteristics, this thesis specifies the required characteristics for trust management mechanisms used to monitor the trustworthiness of entities in a swarm-based autonomic computing system and describes a trust model that meets these requirements.

This dissertation describes a measurement of the mass of the top quark using a method developed by G. Goldstein and R.H. Dalitz. It is based on 2.0 fb{sup -1} of data collected by the Collider Detector Facility at Fermi National Accelerator Laboratories. Di-lepton events were observed from colliding protons with anti-protons with {radical}s = 1.96 TeV in the Tevatron Collider. A total of 145 candidate events were observed with 49 expected to be from background. These events include two neutrinos which elude detection. The method begins by assuming an initial top quark mass and solves for the neutrino momenta using a geometrical construction. The method samples over a range of likely top quark masses choosing the most consistent mass via a likelihood function. An important distinguishing feature of this method from others is its lack of dependence on the missing transverse energy, a quantity that is poorly measured by the experiment. This analysis determines the top quark mass to be M{sub top} = 172.3 {+-} 3.4(stat.) {+-} 2.0(syst.) GeV/c{sup 2} (M{sub top} = 170.5 {+-} 3.7(stat.) {+-} 1.8(syst.) GeV/c{sup 2} with b-tagging).

This dissertation measures the t{bar t} production cross section at the Run II CDF detector using data from early 2001 through March 2007. The Tevatron at Fermilab is a p{bar p} collider with center of mass energy {radical}s = 1.96 TeV. This data composes a sample with a time-integrated luminosity measured at 2.2 {+-} 0.1 fb{sup -1}. A system of learning machines is developed to recognize t{bar t} events in the 'lepton plus jets' decay channel. Support Vector Machines are described, and their ability to cope with a multi-class discrimination problem is provided. The t{bar t} production cross section is then measured in this framework, and found to be {sigma}{sub t{bar t}} = 7.14 {+-} 0.25 (stat){sub -0.86}{sup +0.61}(sys) pb.

In this paper I argue for the need for a strong Science and Technology program in the Nuclear Weapons Complex as the basis for maintaining a credible deterrence capability. The current Nuclear Posture Review establishes a New Triad as the basis for the United States deterrence strategy in a changing security environment. A predictive science capability is at the core of a credible National Nuclear Weapons program in the 21st Century. In absence of nuclear testing, the certification of our current Nuclear Weapons relies on predictive simulations and quantification of the associated simulation uncertainties. In addition, a robust nuclear infrastructure needs an active research and development program that considers all the required nuclear scenarios, including new configurations for which there is no nuclear test data. This paper also considers alternative positions to the need for a Science and Technology program in the Nuclear Weapons complex.

Experimental coincidence cross section and transverse-longitudinal asymmetry A{sub TL} have been obtained for the quasielastic (e,e'p) reaction in {sup 16}O, {sup 12}C, and {sup 208}Pb in constant q-ω kinematics in the missing momentum range -350 < p{sub miss} < 350 MeV/c. In these experiments, performed in experimental Hall A of the Thomas Jefferson National Accelerator Facility (JLAB), the beam energy and the momentum and angle of the scattered electrons were kept fixed, while the angle between the proton momentum and the momentum transfer q was varied in order to map out the missing momentum distribution. The experimental cross section and A{sub TL} asymmetry have been compared with Monte Carlo simulations based on Distorted Wave Impulse Approximation (DWIA) calculations with both relativistic and non-relativistic spinor structure. The spectroscopic factors obtained for both models are in agreement with previous experimental values, while A{sub TL} measurements favor the relativistic DWIA calculation. This thesis describes the details of the experimental setup, the calibration of the spectrometers, the techniques used in the data analysis to derive the final cross sections and the A{sub TL}, the ingredients of the theoretical calculations employed and the comparison of the results with the simulations based on these theoretical models.

A search for Higgs bosons in multijet data from the D0 detector is reported in this thesis. The Higgs boson is the only remaining undiscovered particle in the Standard Model of particle physics, and plays an integral role in this model. It is known that this model is not a complete description of fundamental physics (it does not describe gravity, for example), and so searches for physics beyond the Standard Model are an important part of particle physics. One extension of the Standard Model, the Minimal Supersymmetric Standard Model (MSSM), predicts the existence of five Higgs bosons, two of which can show an enhanced coupling to bottom quarks. For this reason, a search in the bbb (multijet) channel is a sensitive test of Higgs boson physics. The analysis described in this thesis was conducted over 6.6 fb{sup -1} of data. At the time of writing, the best limits on tan {beta} (a key parameter of the MSSM) in the multijet channel were set by D0. The new analysis described in this thesis included more data than the previous analysis in the channel, and made use of a new trigger and event-based analysis method. An improved Multivariate Analysis technique was used …

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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.

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 …

We have presented results in two different yet strongly linked aspects of Higgs boson physics. We have learned about the importance of the Higgs boson for the fate of the Standard Model, being either only a theory limited to explaining phenomena at the electroweak scale or, if the Higgs boson lies within a mass range of 130 < m_H < 160 GeV the SM would remain a self consistent theory up to highest energy scales O(m_Pl). This could have direct implications on theories of cosmological inflation using the Higgs boson as the particle giving rise to inflation in the very early Universe, if it couples non-minimally to gravity, an effect that would only become significant at very high energies. After understanding the immense meaning of proving whether the Higgs boson exists and if so, at which mass, we have presented a direct search for a Higgs boson in associated production with a W boson in a mass range 100 < m_H < 150 GeV. A light Higgs boson is favored regarding constraints from electroweak precision measurements. As a single analysis is not yet sensitive for an observation of the Higgs boson using 5.3 fb^-1 of Tevatron data, we set limits …

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 …

This dissertation focuses on the development of facile and rapid quantitative Raman spectroscopy measurements for the determination of conversion products in producing bioethanol from corn stover. Raman spectroscopy was chosen to determine glucose, xylose and ethanol in complex hydrolysis and fermentation matrices. Chapter 1 describes the motives and main goals of this work, and includes an introduction to biomass, commonly used pretreatment methods, hydrolysis and fermentation reactions. The principles of Raman spectroscopy, its advantages and applications related to biomass analysis are also illustrated. Chapter 2 and 3 comprise two published or submitted manuscripts, and the thesis concludes with an appendix. In Chapter 2, a Raman spectroscopic protocol is described to study the efficiency of enzymatic hydrolysis of cellulose by measuring the main product in hydrolysate, glucose. Two commonly utilized pretreatment methods were investigated in order to understand their effect on glucose measurements by Raman spectroscopy. Second, a similar method was set up to determine the concentration of ethanol in fermentation broth. Both of these measurements are challenged by the presence of complex matrices. In Chapter 3, a quantitative comparison of pretreatment protocols and the effect of enzyme composition are studied using systematic methods. A multipeak fitting algorithm was developed to …

In this Dissertation I present a detailed study of p$\bar{p}$ → WZ production using fully leptonic decays of W and Z bosons with electrons and muons in the final state. Data used for the study were collected by the DØ detector at the Fermilab p$\bar{p}$ collider with a center-of-mass energy of √s = 1.96 TeV and correspond to 4.1 fb^-1 of integrated luminosity. The most precise measurement of the WZ production cross section is obtained and found to be in a good agreement with the standard model prediction. I also present a search for new phenomena in the WZ production by investigating the coupling between W and Z bosons and by searching for new charged particles that can decay into WZ boson pair. No evidence for new physics is found, and the most stringent limits are set on the anomalous WWZ coupling parameters and masses of charged resonances. This result also sets the stringest limit on one of the possible sources of electroweak symmetry breaking, a low-scale Technicolor with a typical heavy techni-pion hypothesis.

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.

Continually rising energy prices have inspired increased interest in weight reduction in the automotive and aerospace industries, opening the door for the widespread use and development of lightweight structural materials. Chief among these materials are cast Al-Si and magnesium-based alloys. Utilization of Al-Si alloys depends on obtaining a modified fibrous microstructure in lieu of the intrinsic flake structure, a process which is incompletely understood. The local solidification conditions, mechanisms, and tensile properties associated with the flake to fiber growth mode transition in Al-Si eutectic alloys are investigated here using bridgman type gradient-zone directional solidification. Resulting microstructures are examined through quantitative image analysis of two-dimensional sections and observation of deep-etched sections showing three-dimensional microstructural features. The transition was found to occur in two stages: an initial stage dominated by in-plane plate breakup and rod formation within the plane of the plate, and a second stage where the onset of out-of-plane silicon rod growth leads to the formation of an irregular fibrous structure. Several microstructural parameters were investigated in an attempt to quantify this transition, and it was found that the particle aspect ratio is effective in objectively identifying the onset and completion velocity of the flake to fiber transition. The appearance …

We present here the search for Standard Model V H → VWW → lll + E_T (missing energy due to neutrinos) production, where V is a W or Z weak vector boson, which uses up to 5.9 fb^-1 of integrated luminosity. This analysis has recently added to the CDF high-mass Higgs group three new signal topologies characterized by a tri-lepton signature, which are chosen to isolate the V H → VWW associated production signals in the three-lepton signature. As such, we define three new regions for a WH analysis, a ZH 1-jet analysis, and a ZH ≥ 2-jet analysis with which we expect to contribute an additional 5.8% (for mH = 165 GeV) acceptance to the current H → WW dilepton analysis. The ZH trilepton regions are defined by events passing a Z-boson selection: events having at least one lepton pairing (among three possible pairings) with opposite sign, same flavor, and a dilepton invariant mass within [76.0, 106.0] GeV–a ± 15 GeV window around the Z-boson mass. TheWH trilepton region is then defined as the set of trilepton events that are complement to those chosen by the Z-boson selection. These three new event topologies make a substantial contribution to the …