We conduct the first study of the T-odd correlations in tt events produced in p{bar p} collision at the Fermilab Tevatron collider that can be used to search for CP violation. We select events which have lepton+jets final states to identify t{bar t} events and measure counting asymmetries of several physics observables. Based on the result, we search the top quark anomalous couplings at the production vertex at the Tevatron. In addition, Geant4 development, photon identification, the discrimination of a single photon and a photon doublet from {pi}{sup 0} decay are discussed in this thesis.

Current understanding of particle physics postulates that there are 17 fundamental particles that interact via four fundamental forces - gravity, the strong force, the weak force, and the electromagnetic force. These fundamental particles can be classified by their spins into bosons, which are the force-carrying particles with integer spins, and fermions, which have half-integer spins. Fermions can be further divided into quarks and leptons. The particles and three of the four forces - all but gravity - are described by the Standard Model, a local SU(3) x SU(2) x U(1) gauge theory. Electromagnetic and weak interactions as described by Electroweak Theory or Quantum Electrodynamics, SU(2) x U(1). Strong interactions are described by Quantum Chromodynamics or QCD, SU(3). Fermions are grouped into three generations as shown in Table 1.1. Each generation consists of a leptonic doublet containing a charged and a neutral lepton and a weak isospin doublet containing two quarks. The first generation, containing the electron, the electron neutrino, the up quark, and the down quark, is the lightest generation and is thus the most frequently found in nature. The second generation contains the muon, the muon neutrino, the strange quark, and the charm quark. The third generation contains the …

The top quark is the heaviest known fundamental particle, with a mass of 172.0{sub -1.3}{sup +0.9}GeV. This is nearly twice the mass of the second heaviest known particle, the Z boson, and roughly the mass of a gold atom. Because of its unusually large mass, studying the top quark may provide insight into the Higgs mechanism and other beyond the standard model physics. Only two accelerators in the world are powerful enough to produce top quarks. The Tevatron, which first accelerated protons in 1983, has produced almost 400,000 top quarks, roughly half at each of its two detectors: DO and CDF. The LHC is a much newer accelerator which currently has accumulated about 0.5% as much data as the Tevatron. However, when running at full luminosity, the LHC is capable of producing a top quark about once every second and will quickly surpass the Tevatron as the leading producer of top quarks. This analysis uses data from the D0 detector at the Tevatron, which are described in chapter 3. Top quarks are produced most often in pairs of top and anti-top quarks through an interaction of the strong force. This production mode was first observed in 1995 at the Tevatron. …

Presented is a series of analyses which are central to the search for a low-mass Higgs boson. A search for ZZ production in the ZZ {yields} {ell}{sup -}{ell}{sup +}{nu}{bar {nu}} channel is introduced then the successful combination of this analysis with with the ZZ {yields} {ell}{sup +}{ell}{sup -}{ell}'{sup +}{ell}'{sup -} search to produce the first observation of the ZZ process at a hadron collider is then detailed. The final analysis presented is the search for the Higgs in the ZH {yields} {nu}{bar {nu}}b{bar b} channel and the interpretation as a ZZ {yields} {nu}{bar {nu}}b{bar b} search in order to validate the techniques. Common themes are discussed, such as multivariate techniques and instrumental backgrounds from energy measurement fluctuations and the tools used to combat them. The formalism of the statistical analysis of the final selected sample is introduced generally and demonstrated in the context of the above mentioned searches. The optimization of the selection through the identification of poorly reconstructed leptons is included as well as the utilization of b-quark identifying tools. Some space is given to jet reconstruction/identification and the Level 1 Calorimeter Trigger. The efficient identification and calibration of jets is central to many physics analysis especially in the …

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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.

A search for the standard model Higgs boson in p{bar p} collisions resulting in two muons and large missing transverse energy is presented. The analysis uses 4.2 fb{sup -1} of integrated luminosity at a center-of-mass energy of {radical}s = 1.96 TeV collected between April 2002 and December 2008 with the D0 detector at the Fermilab Tevatron collider. No significant excess above the background estimation is observed and limits are derived on Higgs boson production.

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 …

Ozone, an ambient pollutant, is transformed into other airborne pollutants in the indoor environment. In this dissertation, the type and amount of byproducts that result from ozone reactions with common indoor surfaces, surface residues, and vapors were determined, pollutant concentrations were related to occupant exposure, and frameworks were developed to predict byproduct concentrations under various indoor conditions. In Chapter 2, an analysis is presented of secondary organic aerosol formation from the reaction of ozone with gas-phase, terpene-containing consumer products in small chamber experiments under conditions relevant for residential and commercial buildings. The full particle size distribution was continuously monitored, and ultrafine and fine particle concentrations were in the range of 10 to>300 mu g m-3. Particle nucleation and growth dynamics were characterized.Chapter 3 presents an investigation of ozone reactions with aircraft cabin surfaces including carpet, seat fabric, plastics, and laundered and worn clothing fabric. Small chamber experiments were used to determine ozone deposition velocities, ozone reaction probabilities, byproduct emission rates, and byproduct yields for each surface category. The most commonly detected byproducts included C1?C10 saturated aldehydes and skin oil oxidation products. For all materials, emission rates were higher with ozone than without. Experimental results were used to predict byproduct exposure …

The analysis presented in this thesis focuses on kinematic distributions in the t{bar t} system and studies in detail selected differential cross sections of top quarks as well as the reconstructed t{bar t} pair, namely the top quark transverse momentum and the t{bar t} system mass. The structure of the thesis is organized as follows: first the Standard Model of the particle physics is briefly introduced in Chapter 1, with relevant aspects of electroweak and strong interactions discussed. The physics of the top quark and its properties are then outlined in Chapter 2, together with the motivation for measuring the transverse top quark momentum and other kinematic-related variables of the t{bar t} system. The concepts of present-day high energy physics collider experiments and the explicit example of Fermilab Tevatron collider and the D0 detector in Chapters 3 and 4 are followed by the description of basic detector-level objects, i.e. tracks, leptons and jets, in Chapter 5; their identification and calibration following in next chapter with the emphasis on the jet energy scale in Chapter 6 and jet identification at the D0. The analysis itself is outlined in Chapter 7 and is structured so that first the data and simulation samples …

In this thesis we present the measurement of the inclusive isolated prompt photon cross section with a total integrated luminosity of 2.5 fb{sup -1} of data collected with the CDF Run II detector at the Fermilab Tevatron Collider. The prompt photon cross section is a classic measurement to test perturbative QCD (pQCD) with potential to provide information on the parton distribution function (PDF), and sensitive to the presence of new physics at large photon transverse momentum. Prompt photons also constitute an irreducible background for important searches such as H {yields} {gamma}{gamma}, or SUSY and extra-dimensions with energetic photons in the final state. The Tevatron at Fermilab (Batavia, U.S.A.) is currently the hadron collider that operates at the highest energies in the world. It collides protons and antiprotons with a center-of-mass energy of 1.96 TeV. The CDF and the D0 experiments are located in two of its four interaction regions. In Run I at the Tevatron, the direct photon production cross section was measured by both CDF and DO, and first results in Run II have been presented by the DO Collaboration based on 380 pb{sup -1}. Both Run I and Run II results show agreement with the theoretical predictions except …

This thesis presents the first measurement of the differential production cross section of a heavy flavor (bottom or charm) jet and direct photon at the Fermilab Tevatron. These measurements were performed using data recorded with the D0 detector from proton-antiproton collisions at a center of mass energy of {radical}s = 1.96 TeV. These results probe a kinematic range for the photon transverse momentum of 30 < p{sub T}{sup {gamma}} < 150 GeV and rapidity of |y{sup {gamma}}| < 1.0 and for jet transverse momentum p{sub T}{sup jet} > 15 GeV and rapidity of |y{sup jet}| < 0.8. These results are compared to next-to-leading-order theoretical calculations.

The past decade is one of the most exciting period in the history of physics and astronomy. The discovery of cosmic acceleration dramatically changed our understanding about the evolution and constituents of the Universe. To accommodate the new acceleration phase into our well established Big Bang cosmological scenario under the frame work of General Relativity, there must exist a very special substance that has negative pressure and make up about 73% of the total energy density in our Universe. It is called Dark Energy. For the first time people realized that the vast majority of our Universe is made of things that are totally different from the things we are made of. Therefore, one of the major endeavors in physics and astronomy in the coming years is trying to understand, if we can, the nature of dark energy. Understanding dark energy cannot be achieved from pure logic. We need empirical evidence to finally determine about what is dark energy. The better we can constrain the energy density and evolution of the dark energy, the closer we will get to the answer. There are many ways to constrain the energy density and evolution of dark energy, each of which leads to …

The existence of the Higgs boson is required by the Standard Model of particle physics, yet it has not been observed. The precise nature of the Higgs boson is unknown and the mechanism by which it interacts with known Standard Model particles is also not known. Long-lived, electrically neutral hadrons have recently been proposed in hidden-valley models and could constitute a pathway through which the Higgs boson communicates with the Standard Model. Such a scenario may provide a novel path to Higgs discovery at the Tevatron. This thesis describes a search for a neutral, long-lived particle produced in decays of Higgs bosons in p{bar p} collisions at a center-of-mass energy of {radical}s = 1.96 TeV, which decays to b-jets and lives long enough to travel at least 1.6 cm before decaying. This analysis uses 3.65 fb{sup -1} of data recorded with the Run II D0 detector at the Fermilab Tevatron collider from April 2002 to August of 2008. We perform a search for eight possible hidden-valley scenarios resulting from a Higgs decay. No significant excess over background is observed and cross-section limits are placed at 95% CL.

This dissertation presents a search for {mu}{sub {nu}} and {bar {mu}{sub {nu}}} disappearance with the MiniBooNE experiment in the {Delta}m{sup 2} region of a few eV{sup 2}. Disappearance measurements in this oscillation region constrain sterile neutrino models and CPT violation in the lepton sector. Fits to the shape of the {mu}{sub {nu}} and {bar {mu}{sub {nu}}} energy spectra reveal no evidence for disappearance in either mode. This is the first test of {bar {mu}{sub {nu}}} disappearance between {Delta}m{sup 2} = 0:1 -- 10 eV2. In addition, prospects for performing a joint analysis using the SciBooNE detector in conjunction with MiniBooNE are discussed.

The BABAR Collaboration is a high energy physics experiment located at the Stanford Linear Accelerator Center. The primary goal of the experiment is to study charge and parity violation in the B-meson sector, however the copious production of B mesons decaying to other final states allows for a wide-ranging physics program. In particular, one can access the charmonium system via colour-suppressed b → c decays of the type B → c$\bar{c}$K. This thesis presents a study of B →c$\bar{c}$γK decays where c$\bar{c}$ includes J/Ψ and Ψ(2S), and K includes K^±, K_S⁰ and K*(892). The particular emphasis is on a search for the radiative decays X(3872) → J/Ψγ and X(3872) → Ψ(2S)γ. The X(3872) state is a recently-discovered resonance of undetermined quark composition, speculatively a conventional charmonium state or exotic four-quark di-meson molecule. This research is also sensitive to the well-known radiative charmonium decays B → χ_c1,2K, which are used as verification for the analysis technique. This dissertation sets the best B → χ_c1K branching fraction measurements to date, and sees the first evidence for factorization-suppressed B⁰ → χ_c2}K*⁰ decay at a level of 3.6σ. It also provides evidence for X(3872) → J/Ψγ and X(3872) → Ψ(2S)γ with 3.6σ and 3.3σ …

The Main Injector Neutrino Oscillation Search (MINOS) is a long baseline neutrino oscillation experiment based at the Fermi National Accelerator Laboratory (FNAL) in Chicago, Illinois. MINOS measures neutrino interactions in two large iron-scintillator tracking/sampling calorimeters; the Near Detector on-site at FNAL and the Far Detector located in the Soudan mine in northern Minnesota. The Near Detector has recorded a large number of neutrino interactions and this high statistics dataset can be used to make precision measurements of neutrino interaction cross sections. The cross section for charged-current quasi-elastic scattering has been measured by a number of previous experiments and these measurements disagree by up to 30%. A method to select a quasi-elastic enriched sample of neutrino interactions in the MINOS Near Detector is presented and a procedure to fit the kinematic distributions of this sample and extract the quasi-elastic cross section is introduced. The accuracy and robustness of the fitting procedure is studied using mock data and finally results from fits to the MINOS Near Detector data are presented.

This Ph.D. thesis presents the measurement of inclusive jet cross sections in Z/{gamma}* {yields} e{sup +}e{sup -} events using 1.7 fb{sup -1} of data collected by the upgraded CDF detector during the Run II of the Tevatron. The Midpoint cone algorithm is used to search for jets in the events after identifying the presence of a Z/{gamma}* boson through the reconstruction of its decay products. The measurements are compared to next-to-LO (NLO) pQCD predictions for events with one and two jets in the final state. The perturbative predictions are corrected for the contributions of non-perturbative processes, like the underlying event and the fragmentation of the partons into jets of hadrons. These processes are not described by perturbation theory and must be estimated from phenomenological models. In this thesis, a number of measurements are performed to test different models of underlying event and hadronization implemented in LO plus parton shower Monte Carlo generator programs. Chapter 2 is devoted to the description of the theory of strong interactions and jet phenomenology at hadron colliders. Chapter 3 contains the description of the Tevatron collider and the CDF detector. The analysis is described in detail in Chapter 4. Chapter 5 shows the measurement of …

We present a search for the production of neutral Higgs bosons in association with bottom quarks in p{bar p} collisions at {radical}s = 1.96 TeV. The cross section for this process is enhanced in many extensions of the Standard Model (SM), such as in its Minimal Supersymmetric extension (MSSM) at large tan {beta}. The data, corresponding to a recorded integrated luminosity of 1 fb{sup -1}, were collected with the D0 detector at the Fermilab Tevatron Collider. In the absence of a signal a 95% C.L. limit is set on the production cross section times branching ratio, and the results are also interpreted in the MSSM.

Images of the Bullet Cluster of galaxies in visible light, X-rays, and through gravitational lensing confirm that most of the matter in the universe is not composed of any known form of matter. The combined evidence from the dynamics of galaxies and clusters of galaxies, the cosmic microwave background, big bang nucleosynthesis, and other observations indicates that 80% of the universe's matter is dark, nearly collisionless, and cold. The identify of the dar, matter remains unknown, but weakly interacting massive particles (WIMPs) are a very good candidate. They are a natural part of many supersymmetric extensions to the standard model, and could be produced as a nonrelativistic, thermal relic in the early universe with about the right density to account for the missing mass. The dark matter of a galaxy should exist as a spherical or ellipsoidal cloud, called a 'halo' because it extends well past the edge of the visible galaxy. The Cryogenic Dark Matter Search (CDMS) seeks to directly detect interactions between WIMPs in the Milky Way's galactic dark matter halo using crystals of germanium and silicon. Our Z-sensitive ionization and phonon ('ZIP') detectors simultaneously measure both phonons and ionization produced by particle interactions. In order to find …

This thesis presents the results on a search for the neutral MSSM Higgs bosons decaying to tau pairs, with least one of these taus decays leptonically. The search was performed with a sample of 1.8 fb{sup -1} of proton-antiproton collisions at {radical}s = 1.96 TeV provided by the Tevatron and collected by CDF Run II. No significant excess over the Standard Model prediction was found and a 95% confidence level exclusion limit have been set on the cross section times branching ratio as a function of the Higgs boson mass. This limit has been translated into the MSSM Higgs sector parameter plane, tan{beta} vs. M{sub A}, for the four different benchmark scenarios.

The cross section for WW production is measured and limits on anomalous WW{gamma} and WWZ trilinear gauge couplings are set using WW {yields} ee/e{mu}/{mu}{mu} events collected by the Run II D0 detector at the Fermilab Tevatron Collider corresponding to 1 fb{sup -1} of integrated luminosity at {radical}s = 1.96 TeV. Across the three final states, 108 candidate events are observed with 40.8 {+-} 3.8 total background expected, consistent with {sigma}(p{bar p} {yields} WW) = 11.6 {+-} 1.8(stat) {+-} 0.7(syst) {+-} 0.7(lumi) pb. Using a set of SU(2){sub L} {direct_product} U(1){sub Y} conserving constraints, the one-dimensional 95% C.L. limits on trilinear gauge couplings are -0.63 < {Delta}{kappa}{sub {gamma}} < 0.99, -0.15 < {lambda}{sub {gamma}} < 0.19, and -0.14 < {Delta}g{sub 1}{sup Z} < 0.34.

We present the first evidence for electroweak single top quark production using nearly 1 fb{sup -1} of Tevatron Run II data at {radical}s = 1.96 TeV. We select single-top-like data events in the lepton+jets decay channel and separate them from backgrounds using the matrix element analysis method. This technique uses leading order matrix elements to compute an event probability for both signal and background hypotheses. Using the expected signal acceptance, background, and observed data we measure the single top quark cross section: {sigma}(p{bar p} {yields} tb + tqb + X) = 4.6{sub -1.5}{sup +}1.8 pb. The probability for the background to have fluctuated up to give at least the cross section measured in this analysis is 0.21%, which corresponds to a Gaussian equivalent significance of 2.9{sigma}.

Since the X(3872) was discovered by the Belle Collaboration in August 2003, it's interpretation through the Standard Model has been difficult. Many possible interpretations have been proposed due to its close proximity to the D{bar D}* mass threshold, ranging from a new state in the charmonium spectrum to a 4-quark state to a weakly bound meson molecule. Probing the X(3872) is also made difficult due to low statistical samples at e{sup +}e{sup -} colliders and large combinatoric backgrounds at hadron colliders such as the Tevatron. This paper presented the results of probes of this state performed at the D0 detector.