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Observation by flow sup 1 H NMR and dimerization kinetics and products of reactive ortho-quinodimethanes and benzocyclobutadiene

Description: The reactive o-quinodimethanes, 1,2-dimethylene-1,2-dihydronaphthalene (9) and o-xylylene (1) were observed by flow {sup 1}H NMR spectroscopy at room temperature. The {sup 1}H NMR spectrum of 9 was obtained in the absence of precursor and dimers. However, the {sup 1}H NMR spectrum of the more reactive 1, generated in a similar manner from (o-((trimethylsilyl)methyl)benzyl)trimethylammonium iodide (5.) could be obtained only in the presence of its stable (4 + 2) and (4 + 4) dimers. The dimerizat… more
Date: September 21, 1990
Creator: Fischer, David
Partner: UNT Libraries Government Documents Department
open access

Diffractive processes in antiproton-proton collision at s**(1/2) = 1.96 TeV in the D0 experiment

Description: A first study of single diffractive central high-p{sub T} dijet events in p{bar p} collisions at center-of-mass energy {radical}s = 1.96 TeV is presented, using data recorded by the D0 detector at the Tevatron during RunIIa in 2002-2004. The total integrated luminosity corresponding to the data sample is 398 pb{sup -1}. A diffractive sample is selected using a rapidity gap approach. A precise definition of the rapidity gap constitutes the first part of the thesis. The rapidity gap is defined by… more
Date: September 1, 2006
Creator: Otec, Roman & /Prague, Tech. U.
Partner: UNT Libraries Government Documents Department
open access

t anti-t production cross section measurement using soft electron tagging in p anti-p collisions at s**(1/2) = 1.96-TeV

Description: We measure the production cross section of t{bar t} events in p{bar p} collisions at {radical}s = 1.96 TeV. The data was collected by the CDF experiment in Run 2 of the Tevatron accelerator at the Fermi National Accelerator Laboratory between 2002 and 2007. 1.7 fb{sup -1} of data was recorded during this time period. We reconstruct t{bar t} events in the lepton+jets channel, whereby one W boson - resulting from the decay of the top quark pairs - decays leptonically and the other hadronically. T… more
Date: September 1, 2008
Creator: Chou, John Paul & U., /Harvard
Partner: UNT Libraries Government Documents Department
open access

Search for 1st Generation Leptoquarks in the eejj channel with the DZero experiment

Description: An evidence of the existence of leptoquarks (LQ) would prove the validity of various extensions of the Standard Model of Particle Physics (SM). The search for first generation leptoquarks presented in this dissertation has been performed by analyzing a 1.02 fb{sup -1} sample of data collected by the D0 detector, events with a final state comprising two light jets and two electrons. The absence of an excess of events in comparison to SM expectations leads to exclude scalar LQ masses up to 292 Ge… more
Date: September 1, 2008
Creator: Barfuss, Anne-Fleur
Partner: UNT Libraries Government Documents Department
open access

Observations and Measurements of Orbitally Excited L=1 B Mesons at the D0 Experiment

Description: This thesis describes investigations of the first set of orbitally excited (L = 1) states for both the B{sub d}{sup 0} and B{sub s}{sup 0} meson systems (B**{sub d} and B**{sub s}). The data sample corresponds to 1.35 fb{sup -1} of integrated luminosity, collected in 2002-2006 by the D0 detector, during the Run IIa operation of the Tevatron p{bar p} colliding beam accelerator. The B**{sub d} states are fully reconstructed in decays to B{sup (*)+} {pi}{sup -}, with B{sup (*)+} {yields} {gamma} J… more
Date: September 1, 2008
Creator: Williams, Mark Richard James
Partner: UNT Libraries Government Documents Department
open access

Search for Higgs Boson Production in Association with the W boson in 1.96-TeV Proton-Antiproton Collisions

Description: A search for the Standard Model Higgs boson was carried out in WH {yields} {ell}{nu}b{bar b} process in p{bar p} collisions at a center of mass energy of 1.96 TeV, where W, H, {ell}, {nu}, b and p denote either a W{sup +} or W{sup -} boson, Higgs boson, lepton (electron or muon), neutrino, bottom quark and proton, respectively. The data were collected with the Collider Detector at Fermilab from February 2002 to August 2004. The corresponding integrated luminosity is 319 pb{sup -1}. We select ev… more
Date: September 1, 2005
Creator: Ishizawa, Yoshio
Partner: UNT Libraries Government Documents Department
open access

Effects of Various Blowout Panel Configurations on the Structural Response of LANL Building 16-340 to Internal Explosions1

Description: The risk of accidental detonation is present whenever any type of high explosives processing activity is performed. These activities are typically carried out indoors to protect processing equipment from the weather and to hide possibly secret processes from view. Often, highly strengthened reinforced concrete buildings are employed to house these activities. These buildings may incorporate several design features, including the use of lightweight frangible blowout panels, to help mitigate blas… more
Date: September 30, 2005
Creator: Wilke, Jason P.
Partner: UNT Libraries Government Documents Department
open access

A Measurement of the Top Quark Mass in 1.96 TeV Proton-Antiproton Collisions Using a Novel Matrix Element Method

Description: A measurement of the top quark mass in t{bar t} {yields} l + jets candidate events, obtained from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector, is presented. The measurement approach is that of a matrix element method. For each candidate event, a two dimensional likelihood is calculated in the top pole mass and a constant scale factor, 'JES', where JES multiplies the input particle jet momenta and is designed to account for the systematic uncer… more
Date: September 30, 2007
Creator: CDF Collaboration
Partner: UNT Libraries Government Documents Department
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Measurement of the top quark pair production cross-section in dimuon final states in proton-antiproton collisions at 1.96 TeV

Description: Particle physics deals with the fundamental building blocks of matter and their interactions. The vast number of subatomic particles can be reduced to twelve fundamental fermions, which interact by the exchange of spin-1 particles as described in the Standard Model (SM) of particle physics. The SM provides the best description of the subatomic world to date, despite the fact it does not include gravitation. Following the relation {lambda} = h/p, where h is Planck's constant, for the examination… more
Date: September 1, 2008
Creator: Konrath, Jens Peter
Partner: UNT Libraries Government Documents Department
open access

A Search for Supersymmetric Higgs Bosons in the Di-tau Decay Mode in Proton - Anti-proton Collisions at 1.8 TeV

Description: A search for directly produced Supersymmetric Higgs Bosons has been performed in the di-tau decay channel in 86.3 {+-} 3.5 pb{sup -1} of data collected by CDF during Run1b at the Tevatron. They search for events where one tau decays to an electron and the other tau decays hadronically. They perform a counting experiment and set limits on the cross section for Higgs production in the high tan {beta} region of the m{sub A}-tan {beta} plane. For a benchmark parameter space point where m{sub A} = 1… more
Date: September 1, 2003
Creator: Connolly, Amy Lynn
Partner: UNT Libraries Government Documents Department
open access

Measurement of the W+- + b anti-b cross-section in 695-pb-1 of p anti-p collisions at CDF II.

Description: W{sup {+-}} + b{bar b} events contain the associated production of a W{sup {+-}} boson, a pair of bottom quarks (b{bar b}), and any number of additional partons. This process is of much importance at hadron collider experiments due to its role as a background source in searches for Standard Model Higgs boson and single top-quark production. In this thesis the results are presented for a measurement of the b-jet cross-section in W{sup {+-}} + b{bar b} events containing 1 or 2 jets in 695 pb{sup … more
Date: September 1, 2006
Creator: Soderberg, Mitchell Paul
Partner: UNT Libraries Government Documents Department
open access

Transition Metal Complexes of Cr, Mo, W and Mn Containing {eta}{sup 1}(S)-2,5-Dimethylthiophene, Benzothiophene and Dibenzothiophene Ligands

Description: The UV photolysis of hexanes solutions containing the complexes M(CO){sub 6} (M=Cr, Mo, W) or CpMn(CO){sub 3} (Cp={eta}{sup 5}-C{sub 5}H{sub 5}) and excess thiophene (T{sup *}) (T{sup *}=2,5-dimethylthiophene (2,5-Me{sub 2}T), benzothiophene (BT), and dibenzothiophene (DBT)) produces the {eta}{sup 1}(S)-T{sup *} complexes (CO){sub 5}M({eta}{sup 1}(S)-T{sup *}) 1-8 or Cp(CO){sub 2}Mn({eta}{sup 1}(S)-T{sup *})9-11, respectively. However, when T{sup *}=DBT, and M=Mo, a mixture of two products resu… more
Date: September 21, 2000
Creator: Reynolds, M.
Partner: UNT Libraries Government Documents Department
open access

Search for Diphoton Events with Large Missing Transverse Energy in 6.3 fb-1 of ppbar Collisions using the D0 Detector at the Fermilab Tevatron Collider

Description: 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 g… more
Date: September 1, 2010
Creator: Cooke, Mark Stephen
Partner: UNT Libraries Government Documents Department
open access

Research in Photosynthesis

Description: The determination of the specific radioactivities of the chlorophylls and carotenoids of algae after photosynthesis with C/sup 14/O/sub 2/ is a formidable task, due to the extreme lability of these compounds. The whole success of the method depends on adequate chromatographic separations of the pigments from the colorless contaminants which are closely associated with them, and yet the time involved for such separations is sufficient for marked decomposition of the pigments to occur. It is sugg… more
Date: September 1, 1959
Creator: Anderson, Joan Mary
Partner: UNT Libraries Government Documents Department
open access

Vibrational inelasticity in H$sub 2$ collisions with He and Li$sup +$

Description: The partially averaged version of classical S-matrix theory was applied to three-dimensional collisions of H$sub 2$ with He and Li$sup +$. For H$sub 2$- Li$sup +$, cross-sections for the de-excitation of H$sub 2$ from (n$sub 1$,j$sub 1$) = (1,0) to the ground vibrational manifold were computed at a total energy of 1.2 eV and compared to previously done coupled channel calculations of Schaefer and Lester. The agreement is very good. For H$sub 2$-He, the Kutzelnigg- Tsapline interaction potential… more
Date: September 1, 1975
Creator: Raczkowski, A.W.
Partner: UNT Libraries Government Documents Department
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DECAY PROPERTIES OF THE E HYPERON AND E RESONANCES

Description: A sample of 2500 {Xi}{sup -} and 500 {Xi}{sup 0} hyperons, produced in {Xi}K, {Xi}K{pi}, and {Xi}K{pi}{pi} final states by K{sup -} (in H{sub 2}) at incident momenta of 1.7 to 2.7 BeV/c, has been analyzed. The data are from an exposure (K-63) of 26 events/{mu}b in the 72-inch bubble chamber; approximately 85% of the {Xi}{sup -} events and 60% of the {Xi}{sup 0} events have been analyzed. For the {Xi}, they determine the spin and decay parameters a{sub {Xi}} and {Phi}{sub {Xi}} = tan{sup -1} ({b… more
Date: September 10, 1966
Creator: Merrill, Jr., Deane W.
Partner: UNT Libraries Government Documents Department
open access

Study of the Ds+ to K+K-e+ nu Decay Channel with the BaBar Experiment

Description: Charm semileptonic decays allow a validation of lattice QCD calculations through the measurement of the hadronic form factors, which characterize the effect of strong interaction in these reactions. The accuracy of such calculations is crucial for the improvement of the test of the standard model in flavor physics. This thesis presents a study of the D{sub s}{sup +} {yields} K{sup +}K{sup -}e{sup +}{nu}{sub e} channel using 214 fb{sup -1} recorded by de BAbar experiment. For events with a K{sup… more
Date: September 9, 2008
Creator: Serrano, Justine & /Orsay, IPN /SLAC
Partner: UNT Libraries Government Documents Department
open access

Measurement of the Top Quark Mass Simultaneously in Dilepton and Lepton + Jets Decay Channels

Description: The authors present the first measurement of the top quark mass using simultaneously data from two decay channels. They use a data sample of {radical}s = 1.96 TeV collisions with integrated luminosity of 1.9 fb{sup -1} collected by the CDF II detector. They select dilepton and lepton + jets channel decays of t{bar t} pairs and reconstruct two observables in each topology. They use non-parametric techniques to derive probability density functions from simulated signal and background samples. The… more
Date: September 1, 2008
Creator: Fedorko, Wojciech T.
Partner: UNT Libraries Government Documents Department
open access

Analysis of Bs flavor oscillations at CDF

Description: The search for and study of flavor oscillations in the neutral B{sub s}B{sub s} meson system is an experimentally challenging task. It constitutes a flagship analysis of the Tevatron physics program. In this dissertation, they develop an analysis of the time-dependent B{sub s} flavor oscillations using data collected with the CDF detector. The data samples are formed of both fully and partially reconstructed B meson decays: B{sub s} {yields} D{sub s}{pi}({pi}{pi}) and B{sub s} {yields} D{sub s}… more
Date: September 1, 2006
Creator: Leonardo, Nuno T.
Partner: UNT Libraries Government Documents Department
open access

Nuclear magnetic relaxation studies of semiconductor nanocrystals and solids

Description: Semiconductor nanocrystals, small biomolecules, and {sup 13}C enriched solids were studied through the relaxation in NMR spectra. Surface structure of semiconductor nanocrystals (CdS) was deduced from high resolution {sup 1}H and {sup 13}C liquid state spectra of thiophenol ligands on the nanocrystal surfaces. The surface coverage by thiophenol was found to be low, being 5.6 and 26% for nanocrystal radii of 11.8 and 19.2 {angstrom}. Internal motion is estimated to be slow with a correlation tim… more
Date: September 1, 1993
Creator: Sachleben, J. R.
Partner: UNT Libraries Government Documents Department
open access

Reaction and reorientation of electronically excited H{sub 2}(B)

Description: The room temperature rate (TR) constants for fluorescence quenching fluorescence of H{sub 2}, HD, and D{sub 2} B {sup 1}{Sigma}{sub u}{sup +} by {sup 4}He were measured as a function of the initially excited rotational and vibrational level of the hydrogen molecule, and the RT rate constants for molecular angular momentum reorientation of H{sub 2}, HD and D{sub 2} (B {sup 1}{Sigma}{sub u}{sup +}. v{prime}=0, J{prime}=1, M{sub J}=0) in collisions with He, Ne, Ar and H{sub 2}(X {sup 1}{Sigma}{sub… more
Date: September 1, 1992
Creator: Pibel, C. D.
Partner: UNT Libraries Government Documents Department
open access

Grid Development and a Study of B-flavour tagging at D�

Description: Run IIa of the D0 experiment at the Tevatron took place between Spring 2002 and Spring 2006, collecting approximately 1.2 fb{sup -1} of data. A fundamental principal of the D0 computing model is the utilization of globally distributed computing resources as part of a grid. In particular use is made of the 'SAMGrid'. The first part of this thesis describes the work undertaken at Imperial College on several D0 distributed computing projects. These included the deployment and development of parts … more
Date: September 1, 2006
Creator: Lewis, Philip William
Partner: UNT Libraries Government Documents Department
open access

Search for Rare Multi-Pion Decays of the Tau Lepton Using the BABAR Detector

Description: A search for the decay of the {tau} lepton to rare multi-pion final states is performed using the BABAR detector at the PEP-II asymmetric-energy e+e- collider. The analysis uses 232 fb-1 of data at center-of-mass energies on or near the {Upsilon}(4S) resonance. In the search for the {tau}- {yields} 3{pi}-2{pi}+2{pi}{sup 0}{nu}{sub {tau}} decay, we observe 10 events with an expected background of 6.5{sup +2.0}{sub -1.4} events. In the absence of a signal, we calculate the decay branching ratio u… more
Date: September 18, 2007
Creator: Ter-Antonyan, Ruben
Partner: UNT Libraries Government Documents Department
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