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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Measurement of the Single Top Quark Production Cross Section and |𝑉𝑡⁢𝑏| in Events with One Charged Lepton, Large Missing Transverse Energy, and Jets at CDF

We report a measurement of single top quark production in proton-antiproton collisions at a center-of-mass energy of √𝑠 = 1.96 TeV using a data set corresponding to 7.5 fb −1 of integrated luminosity collected by the Collider Detector at Fermilab. We select events consistent with the single top quark decay process 𝑡 →𝑊⁢𝑏 →ℓ⁢𝜈⁢𝑏 by requiring the presence of an electron or muon, a large imbalance of transverse momentum indicating the presence of a neutrino, and two or three jets including at least one originating from a bottom quark. An artificial neural network is used to discriminate the signal from backgrounds. We measure a single top quark production cross section of $3.0⁢4^{+0.57}_{−0.53}$ pb and set a lower limit on the magnitude of the coupling between the top quark and bottom quark |𝑉𝑡⁢𝑏|>0.78 at the 95% credibility level.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Some top-quark properties measured in p p-bar collisions using CDF detector at √s = 1.96 TeV (Review)

This review considers important properties of the top-quark. The top-quark decays before hadronization, and the spin information is directly transferred to the decay products. Therefore the structure of the weak interaction is investigated by measuring the helicity fractions, f, of the W boson—the top-quark decay product. Other investigations: search for the presence of V+A interaction, search for exotic top-quark charge — 4/3 and for t t-bar — resonances—all of them, so far, were not found in the experiments — testifies against of going out of the Standard Model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

cDF Theory Software for mesoscopic modeling of equilibrium and transport phenomena

The approach is based on classical Density Functional Theory (cDFT) coupled with the Poisson-Nernst-Planck (PNP) transport kinetics model and quantum mechanical description of short-range interaction and elementary transport processes. The model we proposed and implemented is fully atomistic, taking into account pairwise short-range and manybody long-range interactions. But in contrast to standard molecular dynamics (MD) simulations, where long-range manybody interactions are evaluated as a sum of pair-wise atom-atom contributions, we include them analytically based on well-established theories of electrostatic and excluded volume interactions in multicomponent systems. This feature of the PNP/cDFT approach allows us to reach well beyond the length-scales accessible to MD simulations, while retaining the essential physics of interatomic interactions from first principles and in a parameter-free fashion.

Sushko, Maria↗
DOE OSTI2020

cdf_normalize

The code performs image intensity normalization. A new intensity normalization method is presented, which works well with images whose pixel intensity distribution follow a Gamma Probability Distribution. Some examples are provided to show the normalization effect. This new intensity normalization method is also compared to some other well-established intensity normalization methods.

Mundhenk, TerrellN.↗
DOE OSTI2012

Measurement of the Single Top Quark Cross Section in the Lepton Plus Jets Final State in Proton-Antiproton Collisions at a Center of Mass Energy of 1.96 TeV Using the CDF II Detector

We present a measurement of the single top quark cross section in the lepton plus jets final state using an integrated luminosity corresponding to 7.5 fb -1 of p\bar p collision data collected by the Collider Detector at Fermilab. The single top candidate events are identified by the signature of a charged lepton, large missing transverse energy, and two or three jets with at least one of them identified as originating from a bottom quark. A new Monte Carlo generator POWHEG is used to model the single top quark production processes, which include s-channel, t-channel, and Wt-channel. A neural network multivariate method is exploited to discriminate the single top quark signal from the comparatively large backgrounds. We measure a single top production cross section of $3.04^{+0.57}_{-0.53} (\mathrm{stat.~+~syst.})$ pb assuming $m_{\rm top}=172.5$~GeV/$c^2$. In addition, we extract the CKM matrix element value $|V_{tb}|=0.96\pm 0.09~(\mathrm{stat.~+~syst.})\ ± 0.05~(\mathrm{theory})$ and set a lower limit of $|V_{tb}|>0.78$ at the 95% credibility level.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Heavy flavor decay of Zγ at CDF

Diboson production is an important and frequently measured parameter of the Standard Model. This analysis considers the previously neglected p$\bar{p}$ →Z γ→ b$\bar{b}$ channel, as measured at the Collider Detector at Fermilab. Using the entire Tevatron Run II dataset, the measured result is consistent with Standard Model predictions, but the statistical error associated with this method of measurement limits the strength of this correlation.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Study of Orbitally Excited $B_{(s)}$ Mesons and Evidence for a New $B\pi$ Resonance with the CDF II Detector

This thesis presents an analysis of excited states of B0, B+ and B0 s mesons, decaying to B mesons while emitting a pion or kaon. They are reconstructed from their decay products and a selection is performed to discard wrongly reconstructed B(s) mesons with the multivariate analysis software NeuroBayes, as described in chapter 5. In the training process, the sPlot method and measured and simulated data are used. Chapter 6 describes how the properties of excited B(s) are determined by an unbinned maximum likelihood t to their mass spectra. The systematic uncertainties determined in this analysis are described in chapter 7. The results of this thesis are presented in chapter 8 and a conclusion is given in chapter 9. The results shown in this thesis have been published before in [1].

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Search for Physics Beyond the Standard Model in the Trilepton Signature in $\bar{p}-p$ collisions at $\sqrt{s} = 1.96$~TeV with CDF II

The standard model (SM) of particles and fields is a theory that has proven very accurate in the currently accessible collider energies. Nonetheless, the SM is theoretically incomplete in the sense that it leaves many questions and problems unanswered, for example, the origin of electroweak symmetry breaking (EWSB). The Higgs boson is introduced to the SM to provide a mechanism for electroweak symmetry breaking and masses to quarks and leptons. However, the introduction of the Higgs mechanism has the undesirable effect of introducing the hierarchy problem which is characterized by quadratically divergent contributions to the Higgs mass squared. Supersymmetry (SUSY) has been postulated as a way to solve the problem of the fine tuning of the Higgs self-interactions, and additionally to provide a possible mechanism for EWSB. The golden search channel for mSUGRA is the $\chi{^\pm}_{1} \chi^{0}_{2} \rightarrow 3\ell$ (three leptons) channel. It offers a reasonable signal $\sigma \ x BR$ with very small contributions from Standard Model backgrounds. This thesis, presents a search for chargino-neutralino production within the mSUGRA framework.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Measurement of the inclusive isolated prompt photon cross section in $p\bar{p}$ collisions at $\sqrt{s}=$1.96~TeV, using the full CDF data sample

The measurement of the cross section for the inclusive production of isolated prompt photons in proton-antiproton collisions at $\sqrt{s}$=1.96~TeV is presented. The data set corresponds to an integrated luminosity of 9.5~fb$^{-1}$, collected with the Collider Detector at Fermilab in Run~II. The measurement is performed as a function of the photon transverse energy ($E_T^{\gamma}$) covering the range of 30~GeV$< E_T^{\gamma} <$500~GeV in the pseudorapidity region $|\eta^{\gamma}|<$1.0. To reduce the background coming from the decays of $\pi^0$'s, $\eta$'s and other hadrons, photons are required to be isolated in the calorimeter. The output distributions of an Artificial Neural Network are exploited to estimate the remaining contamination from jets faking isolated photons. Results are compared to leading-order and next-to-leading-order perturbative QCD calculations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Measurement of the Exclusive and Inclusive Branching Fractions of $B^{0}_{s} \to D^{(*)+}_{s}D^{(*)-}_{s}$ Decays at CDF and its Implications on the Decay Width Difference in the $B^{0}_{s}-B^{-0}_{s}$ Meson System

The purpose of this thesis is threefold: Firstly, new measurements of both the exclusive and semi-inclusive partial decay widths of $B^{0}_{s} \to D^{(*)+}_{s}D^{(*)-}_{s}$ meson decays are presented. Secondly, the feasibility of extracting the unknown polarization components in $B^{0}_{s} \to D^{(*)+}_{s}D^{(*)-}_{s}$ by partial reconstruction of this pseudo-scalar to vector-vector decay in a Monte Carlo driven analysis scheme is studied. Finally, based on the suggestions contributed by the theory community this study discusses how a measurement of the branching fraction of semi-inclusive decays $B^{0}_{s} \to D^{(*)+}_{s}D^{(*)-}_{s}$ can contribute to gain insight about the relative decay width di erence in the B$0\atop{s}$--B$0\atop{s}$ meson system.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Measurement of $W$ -Boson Helicity-Fractions in Top-Quark Decays with the CDF II Experiment and Prospects for an Early $t\overline{t}$ Cross-Section Measurement with the CMS Experiment

Aus was besteht die Welt? Die Frage nach den fundamentalen Bausteinen der Materie beschaftigte Wissenschaftler und Gelehrte zu allen Zeiten. Ausgehend von abstrakten philosophischen Uberlegungen wurde das Konzept von kleinsten, nicht weiter zerteilbaren Grundbausteinen der Materie bereits einige Jahrhunderte vor Christus von indischen und griechischen Philosophieschulen entwickelt. Etwa 450 v. Chr. pragte Demokrit den Begriff ´atomos, das “Unzerschneidbare”, fur die diskreten Grundbausteine der Materie. Doch erst in der jungeren Vergangenheit konnte dieses philosophische Konzept auch experimentell uberpruft werden.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Search for neutral MSSM Higgs bosons in association with b quarks in the tau-tau decay channels at CDF Run II

This thesis presents the results of a search for neutral MSSM Higgs bosons decaying to ττ with 5.9 fb. –1 of data. The analysis requires at least one of the taus to decay leptonically, and explores three detection modes in two channels: τeτ μ , τeτ had , and τμτ had , where the index denotes the type of tau decay. In all modes we explore the tagged and untagged channel. No signal is observed limits were set on σ( p$\bar{p}$ → Φ + X) × BR(Φ → ττ) as a function of Higgs mass. The results are also interpreted as exclusions of parameter space in the tanβ vs m A plane for several benchmark scenarios.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Measurement of $B/s$ lifetime, decay width difference and polarization amplitude of the $B/s\to J/\Psi \phi$ decays at CDF II

In this thesis the update of the measurement of the B$^{0}_{s}$ lifetime, the decay width difference between its heavy and light mass eigenstates and the polarization amplitudes of B$^{0}_{s}$ $\rightarrow$ J/$\psi\phi$ decays of the $^{0}_{s}$ meson is presented. About 9600 B$^{0}_{s}$ → J/ψφ decays have been reconstructed in the final state [$\mu^{+}$ $\mu^{−}$ ][K$^{+}$K$^{-}$ ] using a dataset of p ̄$\overline{p}$ collisions at $\sqrt{s}$ = 1.96 TeV corresponding to 8.4 fb$^{-1}$ integrated luminosity collected by the CDFII detector at the Fermilab Tevatron collider. The results are extracted from an analysis of the angular distributions of muons and kaons as a function of the decay time through an unbinned maximum likelihood fit which exploits identification of the quark content (b or $\overline{b}$ of the strange bottom meson at the time of production. Assuming the Standard Model prediction for the size of CP violation occurring in the B$^{0}_ {s}$ mixing, the estimated lifetime, decay width difference, polarization amplitudes and strong phase of the perpendicular amplitude are: τ (B$^{0}_{s}$) = 1.527 $\pm$ 0.021(stat.)ps, $\Delta\Gamma$ = 0.063 $\pm$ 0.029(stat.)ps$^{-1}$, $\mid$A$_{parallel}$ (0)$\mid^{2}$ = 0.233 $\pm$ 0.014(stat.), $\mid$A$_[0}$ $\mid^{2}$ = 0.514 $\pm$ 0.012(stat.), $\delta_{perpendicular}$ = 2.95 $\pm$ 0.61(stat.)

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗