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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

Beam Dynamics in a Muon Ionisation Cooling Channel

Description: The Neutrino Factory has been proposed as a facility to provide an intense source of neutrinos suitable for the measurement of neutrino oscillation parameters and a possible CP violating phase to unprecedented precision. In the Neutrino Factory, neutrinos are produced by the decay of a muon beam with 20-50 GeV per muon. Initially, the muon beam occupies a large volume in phase space, which must be reduced before the beam can be accelerated. The proposed method to achieve this is to use a soleno… more
Date: September 1, 2008
Creator: Rogers, Chris
Partner: UNT Libraries Government Documents Department
open access

Coupling of the 4f Electrons in Lanthanide Molecules

Description: (C5Me5)2LnOTf where Ln = La, Ce, Sm, Gd, and Yb have been synthesized and these derivatives are good starting materials for the synthesis of (C5Me5)2LnX derivatives. (C5Me5)2Ln(2,2'-bipyridine), where Ln = La, Ce, Sm, and Gd, along with several methylated bipyridine analogues have been synthesized and their magnetic moments have been measured as a function of temperature. In lanthanum, cerium, and gadolinium complexes the bipyridine ligand ligand is unequivocally the radical anion, and the obse… more
Date: September 12, 2008
Creator: Kazhdan, Daniel
Partner: UNT Libraries Government Documents Department
open access

An Enquiry Concerning Charmless Semileptonic Decays of Bottom Mesons

Description: The branching fractions for the decays B {yields} P{ell}{nu}{sub {ell}}, where P are the pseudoscalar charmless mesons {pi}{sup {+-}}, {pi}{sup 0}, {eta} and {eta}{prime} and {ell} is an electron or muon, are measured with B{sup 0} and B{sup {+-}} mesons found in the recoil of a second B meson decaying as B {yields} D{ell}{nu}{sub {ell}} or B {yields} D*{ell}{nu}{sub {ell}}. The measurements are based on a data set of 348 fb{sup -1} of e{sup +}e{sup -} collisions at {radical}s = 10.58 GeV recor… more
Date: September 19, 2008
Creator: Chaisanguanthum, Kris Somboon & /SLAC, /Harvard U.
Partner: UNT Libraries Government Documents Department
open access

The Lifetime of a beautiful and charming meson: B_c lifetime measured using the D0 detector

Description: Using approximately 1.3 fb{sup -1} of data collected by the D0 detector between 2002 and 2006, the lifetime of the B{sub c}{sup {+-}} meson is studied in the B{sub c}{sup {+-}} {yields} J/{psi}{mu}{sup {+-}} + X final state. Using an unbinned likelihood simultaneous fit to J/{psi} + {mu} invariant mass and lifetime distributions, a signal of 810 {+-} 80(stat.) candidates is estimated and a lifetime measurement made of: {tau}(B{sub c}{sup {+-}}) = 0.448{sub -0.036}{sup +0.038}(stat) {+-} 0.032(s… more
Date: September 1, 2008
Creator: Welty-Rieger, Leah Christine
Partner: UNT Libraries Government Documents Department
open access

Measurement of the Λ<sup>0</sup><sub>b</sub> lifetime in Λ<sup>0</sup><sub>b</sub> → Λ<sup>+</sup><sub>c</sub>π<sup>-</sup> decays at the Collider Detector at Fermilab

Description: The lifetime of the Λ<sup>0</sup><sub>b</sub> baryon (consisting of u, d and b quarks) is the theoretically most interesting of all b-hadron lifetimes. The lifetime of Λ<sup>0</sup><sub>b</sub> probes our understanding of how baryons with one heavy quark are put together and how they decay. Experimentally however, measurements of the Λ<sup>0</sup><sub>b</sub> lifetime have either lacked precision or have been inconsistent with one another. This thesis describes the measurement of Λ<sup>0</sup><… more
Date: September 1, 2008
Creator: Mumford, Jonathan Reid
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

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

Measurement of the top quark pair production cross section in the dilepton channel using lepton+track selection

Description: The production cross section for t{bar t} pairs decaying into two lepton final states was measured using data from the D0 detector at Fermilab. The measurement was made using a lepton+track selection, where one lepton is fully identified and the second lepton is observed as an isolated track. This analysis is designed to complement similar studies using two fully identified leptons [1]. The cross section for the lepton+track selection was found to be {sigma} = 5.2{sub -1.4}{sup +1.6}(stat){sub … more
Date: September 1, 2008
Creator: Wagner, Robert Emil
Partner: UNT Libraries Government Documents Department
open access

Measuring Antineutrino Oscillations with the MINOS Experiment

Description: MINOS is a long baseline neutrino oscillation experiment. A manmade beam of predominantly muon neutrinos is detected both 1 km and 735 km from the production point by two functionally identical detectors. A comparison of the energy spectra measured by the two detectors shows the energy-dependent disappearance of muon neutrinos characteristic of oscillations and allows a measurement of the parameters governing the oscillations. This thesis presents work leading to measurements of disappearance i… more
Date: September 1, 2008
Creator: Evans, Justin John
Partner: UNT Libraries Government Documents Department
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Mesure DE La Section Efficace DE Production DE Paires DE Quarks Top Dans L'Etat Final DI-Electron Avec Les Donnees Collectees Par L'Experience d0 AU Runiia

Description: The top quark has been discovered in 1995 by CDF and D0 collaborations in proton-antiproton collisions at the Tevatron. The amount of data recorded by both experiments makes it possible to accurately measure the properties of this very massive quark. This thesis is devoted to the measurement of the top pair production cross-section via the strong interaction, in a final state composed of two electrons, two particle jets and missing transverse energy. It is based on a 1 fb{sup -1} data set colle… more
Date: September 1, 2008
Creator: Martin Dit Latour, Bertrand & /LPSC, Grenoble
Partner: UNT Libraries Government Documents Department
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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 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

Search for B to rho/omega gamma decays at BaBar

Description: The authors present the results of the search for the decays B{sup 0/{+-}} {yields} {rho}{sup 0/{+-}}{gamma} (previously observed) and B{sup 0} {yields} {omega}{gamma} (for which currently only an upper limit exists). Together with B {yields} K*{gamma} decays, B {yields} ({rho}/{omega}){gamma} allow us to measure the ratio of CKM-matrix elements |V{sub td}/V{sub ts}|. The analysis is based on the full BABAR dataset of 424.35 fb{sup -1} corresponding to 465 million B{bar B} pairs, and makes heav… more
Date: September 23, 2008
Creator: Piatenko, Timofei & /SLAC, /Caltech
Partner: UNT Libraries Government Documents Department
open access

Search for Higgs Bosons and Supersymmetric Particles in Tau Final States

Description: Elementary particle physics tries to find an answer to no minor question: What is our universe made of? To our current knowledge, the elementary constituents of matter are quarks and leptons, which interact via four elementary forces: electromagnetism, strong force, weak force and gravity. All forces, except gravity, can be described in one framework, the Standard Model of particle physics. The model's name reflects its exceptional success in describing all available experimental high energy ph… more
Date: September 1, 2008
Creator: Torchiani, Ingo & U, /Freiburg
Partner: UNT Libraries Government Documents Department
open access

A Search for Neutrinoless Tau Decays to Three Leptons

Description: Using approximately 350 million {tau}{sup +}{tau}{sup -} pair events recorded with the BaBar detector at the Stanford Linear Accelerator Center between 1999 and 2006, a search has been made for neutrinoless, lepton-flavor violating tau decays to three lighter leptons. All six decay modes consistent with conservation of electric charge and energy have been considered. With signal selection efficiencies of 5-12%, we obtain 90% confidence level upper limits on the branching fraction {Beta}({tau} {… more
Date: September 24, 2008
Creator: Kolb, Jeffrey A. & /SLAC, /Oregon U.
Partner: UNT Libraries Government Documents Department
open access

A study of Central Exclusive Production

Description: Central exclusive production of a system X in a collision between two hadrons h is defined as hh {yields} h + X + h with no other activity apart from the decay products of X. This thesis presents predictions for the production cross section of a CP violating supersymmetric Higgs boson and the radion of the Randall-Sundrum model. The ExHuME Monte Carlo generator was written to simulate central exclusive processes and is described and explored. A comparison to di-jet observations made by the D0 d… more
Date: September 1, 2008
Creator: Monk, James
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
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