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open access

Search for heavy metastable particles decaying to quark pairs at CDF

Description: We report on the search for heavy metastable particles that decay into quark pairs with a macroscopic lifetime (c{tau} {approx} 1 cm) using data taken with the CDF II detector at Fermilab. We use a data driven background approach, where they build probability density functions to model Standard Model secondary vertices from known processes in order to estimate the background contribution from the Standard Model. No statistically significant excess is observed above the background. Limits on the… more
Date: March 1, 2011
Creator: Kwang, Shawn Andrew
Partner: UNT Libraries Government Documents Department
open access

Search for the Standard Model Higgs Boson in Missing Transverse Energy and $b$-quark Final States Using Proton-Antiproton Collisions at 1.96 TeV

Description: A search for the standard model Higgs boson is performed in 6.4 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV, collected with the D0 detector during Run II of the Fermilab Tevatron. The final state considered is a pair of jets originating from b quarks and missing transverse energy, as expected from p{bar p} {yields} ZH {yields} {nu}{bar {nu}}b{bar b} production. The search is also sensitive to the WH {yields} {ell}{nu}b{bar b} channel, where the charged lepton is not identified. B… more
Date: March 1, 2011
Creator: Dorland, Tyler M. & /Washington U., Seattle
Partner: UNT Libraries Government Documents Department
open access

Energy Spread Reduction of Electron Beams Produced via Laser Wake

Description: Laser wakefield acceleration of electrons holds great promise for producing ultra-compact stages of GeV scale, high quality electron beams for applications such as x-ray free electron lasers and high energy colliders. Ultra-high intensity laser pulses can be self-guided by relativistic plasma waves over tens of vacuum diffraction lengths, to give >1 GeV energy in cm-scale low density plasma using ionization-induced injection to inject charge into the wake at low densities. This thesis descri… more
Date: March 19, 2012
Creator: Pollock, B.
Partner: UNT Libraries Government Documents Department
open access

Investigation of high-precision {Lambda} hypernuclear spectroscopy via the (e,e'K{sup +}) reaction

Description: The study of {Lambda} hypernuclear structure is very interesting in point of the understanding of the interaction between {Lambda} and nucleon ({Lambda}-N interaction) and its ”strange” structure itself due to the containment of a {Lambda} hyperon which has a strangeness as a new degree of freedom. In the several way to study the Lamda hypernuclei, the (e,e'K{sup +}) reaction spectroscopy is a powerful tool for the precise investigation of {Lamda} hypernuclear structure. The purpose of the… more
Date: March 31, 2012
Creator: Kawama, Daisuke
Partner: UNT Libraries Government Documents Department
open access

Precision Measurements of Tau Lepton Decays

Description: Using data collected with the BABAR detector at the SLAC PEP-II electron-positron storage ring operating at a center-of-mass energy near 10.58 GeV, the branching fractions {Beta}({tau}{sup -} {yields} {pi}{sup -}{pi}{sup -}{pi}{sup +}{nu}{sub {tau}}) = (8.83 {+-} 0.01 {+-} 0.13)%, {Beta}({tau}{sup -} {yields} K{sup -}{pi}{sup -}{pi}{sup +}{nu}{sub {tau}}) = (0.273 {+-} 0.002 {+-} 0.009)%, {Beta}({tau}{sup -} {yields} K{sup -}{pi}{sup -}K{sup +}{nu}{sub {tau}}) = (0.1346 {+-} 0.0010 {+-} 0.0036)… more
Date: March 16, 2010
Creator: Nugent, Ian M.
Partner: UNT Libraries Government Documents Department
open access

Measurement of the $WW+WZ$ production cross section in a semileptonic decay mode at CDF

Description: 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 … more
Date: March 1, 2010
Creator: Hurwitz, Martina
Partner: UNT Libraries Government Documents Department
open access

Rhodium mediated bond activation: from synthesis to catalysis

Description: Recently, our lab has developed monoanionic tridentate ligand, To{sup R}, showing the corresponding coordination chemistry and catalyst reactivity of magnesium, zirconium, zinc and iridium complexes. This thesis details synthetic chemistry, structural study and catalytic reactivity of the To{sup R}-supported rhodium compounds. Tl[To{sup R}] has been proved to be a superior ligand transfer agent for synthesizing rhodium complexes. The salt metathesis route of Tl[To{sup M}] with [Rh({mu}-Cl)(CO)]… more
Date: March 6, 2012
Creator: Ho, Hung-An
Partner: UNT Libraries Government Documents Department
open access

Study of the (e,e'p) quasi-elastic reaction in complex nuclei: theory and experiment

Description: 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 … more
Date: March 1, 2010
Creator: Herraiz, Joaquin Lopez
Partner: UNT Libraries Government Documents Department
open access

Testing CPT conservation using the NuMI neutrino beam with the MINOS experiment

Description: 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%$\bar{v}$<sub>μ</sub>, which can be separated from the v<sub>μ</sub> because the MINOS detectors are magnetized. Thi… more
Date: March 1, 2010
Creator: Auty, David John
Partner: UNT Libraries Government Documents Department
open access

Measurement of the single top production cross section in proton-antiproton collisions at 1.96 TeV

Description: This thesis describes a search for singly produced top quarks via an electroweak vertex in head-on proton-antiproton collisions at a center of mass energy of √s = 1.96 TeV. The analysis uses a total of 2.3 fb<sup>-1</sup> of data collected with the D0 detector at Fermilab, corresponding to two different run periods of the Tevatron collider. Two channels contribute to single top quark production at the Tevatron, the s-channel and the t-channel. In the s-channel, a virtual W boson is produced fro… more
Date: March 25, 2010
Creator: Tanasijczuk, Andres Jorge
Partner: UNT Libraries Government Documents Department
open access

Rhodium Catalysts in the Oxidation of CO by O<sub>2</sub> and NO: Shape, Composition, and Hot Electron Generation

Description: It is well known that the activity, selectivity, and deactivation behavior of heterogeneous catalysts are strongly affected by a wide variety of parameters, including but not limited to nanoparticle size, shape, composition, support, pretreatment conditions, oxidation state, and electronic state. Enormous effort has been expended in an attempt to understand the role of these factors on catalytic behavior, but much still remains to be discovered. In this work, we have focused on deepening the pr… more
Date: March 8, 2010
Creator: Renzas, James R.
Partner: UNT Libraries Government Documents Department
open access

Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

Description: This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dis… more
Date: March 14, 2013
Creator: Meyer, Matthew W.
Partner: UNT Libraries Government Documents Department
open access

First observation of the Charmless Decay B to K pi0pi0 and Study of its Dalitz Plot Structure

Description: Results for the first measurement of the inclusive branching and CP asymmetry of the charmless 3-body decay B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0} are presented. The analysis uses a data sample with an integrated luminosity of 429.0 fb{sup -1}, recorded by the BABAR detector at the PEP-II asymmetric B Factory. This sample corresponds to 470.9 {+-} 2.8 million B{bar B} pairs. Measurements of the branching fractions (B) and CP asymmetries (A{sub CP}) of some of the intermediate resonanc… more
Date: March 21, 2012
Creator: Puccio, Eugenia Maria Teresa Irene & /SLAC, /Warwick U.
Partner: UNT Libraries Government Documents Department
open access

Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators

Description: The longitudinal beam dynamics in circular accelerators is mainly defined by the interaction of the beam current with the accelerating Radio Frequency (RF) stations. For stable operation, Low Level RF (LLRF) feedback systems are employed to reduce coherent instabilities and regulate the accelerating voltage. The LLRF system design has implications for the dynamics and stability of the closed-loop RF systems as well as for the particle beam, and is very sensitive to the operating range of accele… more
Date: March 1, 2011
Creator: Mastoridis, Themistoklis & /Stanford U., Elect. Eng. Dept. /SLAC
Partner: UNT Libraries Government Documents Department
open access

Search for New and Unusual Stangonia using CLAS

Description: We perform a survey of the proton, K^+, K^- -3 charged track data, taken by the CLAS detector for the HyCLAS experiment during the g12 run-period at Jefferson Lab. We aim to study the strong decay amplitudes, partial widths and production channels of strangeonia from the CLAS g12 dataset. HyCLAS was motivated by the experimental results for gluonic hybrid meson candidates, theoretical Lattice QCD, and Flux-tube Model calculations and predictions. The experiment was designed and conducted to sea… more
Date: March 1, 2013
Creator: Saini, Mukesh Satyapraka
Partner: UNT Libraries Government Documents Department
open access

Search for new particles decaying to diject in 7 TeV proton-proton collisions at CMS

Description: This thesis presents a measurement of the dijet invariant mass spectrum and search for new particles decaying to dijets at CMS in 7 TeV pp collisions using data corresponding to an integrated luminosity of 2.875 pb{sup -1}. The measured dijet mass distribution is compared to QCD prediction from PYTHIA . It is required the pseudorapidity separation of the two jets to satisfy |Dh| &lt; 1.3 with each jet inside the region of |{eta}| &lt; 2.5. The observed dijet mass spectrum is fitted by a smooth … more
Date: March 1, 2011
Creator: Ozturk, Sertac & U., /Cukurova
Partner: UNT Libraries Government Documents Department
open access

Measurement of the D_s Decay Constant f_Ds and Observation of New Charm Resonances Decaying to D^(*)\pi

Description: The absolute branching fractions for the decays D{sub s}{sup -} {yields} {ell}{sup -}{bar {nu}}{sub {ell}} ({ell} = e, {mu}, or {tau}) are measured using a data sample corresponding to an integrated luminosity of 521 fb{sup -1} collected at center of mass energies near 10.58 GeV with the BABAR detector at the PEPII e{sup +}e{sup -} collider at SLAC. The number of D{sub s}{sup -} mesons is determined by reconstructing the recoiling system DKX{gamma} in events of the type e{sup +}e{sup -} {yields… more
Date: March 15, 2012
Creator: Benitez, Jose
Partner: UNT Libraries Government Documents Department
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