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A measurement of the top quark's charge

Description: The top quark was discovered in 1995 at the Fermilab National Accelerator Laboratory (Fermilab). One way to confirm if the observed top quark is really the top quark posited in the Standard Model (SM) is to measure its electric charge. In the Standard Model the top quark is the isospin partner of the bottom quark and is expected to have a charge of +2/3. However, an alternative 'exotic' model has been proposed with a fourth generation exotic quark that has the same characteristics, such as mass… more
Date: November 1, 2007
Creator: Unalan, Zeynep Gunay
Partner: UNT Libraries Government Documents Department
open access

A Search for Direct CP Violation in Two-Body Cabibbo-Suppressed Decays of Neutral Charmed Mesons

Description: Presented are the results of a search for direct CP violation in Cabibbo-suppressed decays of D{sup 0} to two charged daughters. The analysis described was performed on {approx}230 fb{sup -1} of the BABAR data sample, recorded at the Stanford Linear Accelerator Center and using the PEP-II electron storage rings. We measure CP asymmetries for decay to the KK and {pi}{pi} final states, as well as for the branching ratio, and develop a new technique for tagging-efficiency correction using the Cabi… more
Date: November 12, 2007
Creator: Flacco, Christian Julienne & /UC, Santa Cruz
Partner: UNT Libraries Government Documents Department
open access

First measurement of top quark pair production cross-section in muon plus hadronic tau final states

Description: This dissertation presents the first measurement of top quark pair production cross-section in events containing a muon and a tau lepton. The measurement was done with 1 fb{sup -1} of data collected during April 2002 through February 2006 using the D0 detector at the Tevatron proton-antiproton collider, located at Fermi National Accelerator Laboratory (Fermilab), Batavia, Illinois. Events containing one isolated muon, one tau which decays hadronically, missing transverse energy, and two or more… more
Date: November 1, 2007
Creator: Sumowidagdo, Suharyo
Partner: UNT Libraries Government Documents Department
open access

Measurement of z boson transverse momentum in proton - anti-proton collisions at s**(1/2) = 1.96 TeV

Description: This dissertation describes a measurement of the shape of the boson transverse momentum distribution in p{bar p} {yields} Z/{gamma}* {yields} e{sup +}e{sup -} + X events at a center-of-mass energy of 1.96 TeV. The measurement is made for events with electron-positron mass between 70 < M{sub ee} < 110 GeV/c{sup 2} and uses 976 pb{sup -1} of data collected at the Fermilab Tevatron collider with the D0 detector. The shape is measured both for the inclusive sample and for the subset of events… more
Date: November 1, 2007
Creator: Wang, Lei
Partner: UNT Libraries Government Documents Department
open access

Single-Mode VISAR

Description: High energy-density physics (HEDP) experiments examine the properties of materials under extreme conditions. These experiments rely on the measurement of one or two velocities. These velocities are used to obtain Hugoniot relationships and thermodynamic equations of state. This methodology is referred to as 'velocimetry' and an instrument used to measure the shock wave is called a 'velocimeter' or a '(velocity) diagnostic'. The two most-widely used existing velocity diagnostics are; photonic Do… more
Date: November 16, 2007
Creator: Krauter, K
Partner: UNT Libraries Government Documents Department
open access

Search for new heavy charged gauge bosons

Description: Additional gauge bosons are introduced in many theoretical extensions to the Standard Model. A search for a new heavy charged gauge boson W{prime} decaying into an electron and a neutrino is presented. The data used in this analysis was taken with the D0 detector at the Fermilab proton-antiproton collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of about 1 fb{sup -1}. Since no significant excess is observed in the data, an upper limit is set on the prod… more
Date: November 1, 2007
Creator: Magass, Carsten Martin & U., /RWTH Aachen
Partner: UNT Libraries Government Documents Department
open access

Measurement of the lifetime difference and cp-violating phase in B_s -> J/psi phi decays

Description: Over the past decades the current theoretical description, the Standard Model of elementary particle physics, was solidified by many measurements as the basic theory describing fundamental particles and their interactions. It is extremely successful in explaining the high-precision data collected by experiments so far. The Standard Model includes several intrinsic parameters which have to be measured in experiments. Independent analyses of different physical processes can constrain those parame… more
Date: November 1, 2007
Creator: Milnik, Michael
Partner: UNT Libraries Government Documents Department
open access

Search for electroweak single top-quark production with the CDF II experiment

Description: Understanding the world -- This aim drives humankind since the beginning of conscious thinking. Especially the nature of matter has been of major interest. Nowadays, we have a complex image of the constitution of matter. Atoms consist of electrons and nucleons. But even nucleons are not elementary. Their basic constituents are called quarks. Physicists developed a model describing the elementary components of matter as well as the forces between them: the standard model of elementary particle p… more
Date: November 1, 2007
Creator: Richter, Svenja
Partner: UNT Libraries Government Documents Department
open access

First Observation of An Excited Charm Baryon Decaying to Omega Charm Baryon at the BaBar Experiment

Description: We have carried out a search for a charmed baryon {Omega}{sup *}{sub c} decaying to {Omega}{sup 0}{sub c} and a {gamma} where {Omega}{sub c} candidates are reconstructed using decay modes {Omega}{sup -}{pi}{sup +}(c1), {Omega}{sup -}{pi}{sup +}{pi}{sup 0}(c2), {Omega}{sup -}{pi}{sup +}{pi}{sup -}{pi}{sup +}(c3) and {Xi}{sup -}K{sup -}{pi}{sup +}{pi}{sup +}(c4). This search is performed by analyzing integrated luminosity of 230.7 fb{sup -1} data collected by the BABAR detector at the Stanford Li… more
Date: November 26, 2007
Creator: Bula, Rahmi & /SUNY, Albany
Partner: UNT Libraries Government Documents Department
open access

A search for muon neutrino to electron neutrino oscillations at delta(m^2)>0.1 eV^2

Description: The evidence is compelling that neutrinos undergo flavor change as they propagate. In recent years, experiments have observed this phenomenon of neutrino oscillations using disparate neutrino sources: the sun, fission reactors, accelerators, and secondary cosmic rays. The standard model of particle physics needs only simple extensions - neutrino masses and mixing - to accommodate all neutrino oscillation results to date, save one. The 3.8{sigma}-significant {bar {nu}}{sub e} excess reported by … more
Date: November 1, 2007
Creator: Patterson, Ryan Benton
Partner: UNT Libraries Government Documents Department
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