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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Search for Anomalous Production of Photon + Jets + Missing Transverse Energy in $p\bar{p}$ Collisions at $\sqrt{s}=1.96$~TeV Using the CDF II Detector

A model-independent signature-based search for physics beyond the Standard Model is performed in the photon + jets + missing transverse energy channel in \ppbar collisions at a center of mass energy of 1.96 TeV using the CDF II detector. Events with a photon + jets are predicted by the Standard Model and also by many theoretical models beyond the Standard Model. In the Standard Model, the main mechanisms for photon + jets production include quark-antiquark annihilation and quark-gluon scattering. No intrinsic missing transverse energy is present in any of these Standard Model processes. In this search, photon + $\geq$1 jet and photon + $\geq$2 jet events are analyzed with and without a minimum requirement on the missing transverse energy. Numerous mass distributions and kinematic distributions are studied and no significant excess over the background prediction is found. All results indicate good agreement with expectations of the Standard Model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Measurement of CP–Violating Asymmetries in $D^0 \to \pi^+ \pi^-$ and $D^0 \to K^+ K^- $ Decays at CDF

We report a search for non–Standard Model physics through the measurement of CP–violating asymmetries in the singly–Cabibbo– suppressed $D^0 \to \pi^+ \pi^-$ and $D^0 \to K^+ K^- $ decays reconstructed in about 5.9 fb-1 of CDF data. We use the strong $D^{*+} \to D^0\pi^+$ decay (“D tag”) to identify the flavor of the charmed meson at production time and exploit CP–conserving strong cc pair–production in pp collisions. Large samples of Cabibbo–favored $D^0 \to K^-\pi^+$ decays with and without D tag are used to highly suppress systematic uncertainties due to detector effects. The results are the world’s most precise measurements to date and have been published by Physical Review D in January 2012 [1].

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Charmed Baryon Spectroscopy and Search for $CP$ Violation in $D^0 \to K_S^0\,\pi^+\,\pi^-$ at CDF

In this thesis two different analyses are presented, namely the measurements of the properties of $\Lambda_c(2595)^+$, $\Lambda_c(2625)^+$, $\Sigma_c(2455)^{++,0}$, and $\Sigma_c(2520)^{++,0}$ baryons as well as the search for $CP$ violation in the Dalitz plot of the decay $D^0 \to K_S^0\,\pi^+\,\pi^-$. Both studies are performed using data corresponding to 5.2\,\invfb respective 6.0\,\invfb of integrated luminosity from $p\bar{p}$ collisions at a center-of-mass energy of 1.96\,TeV, collected with the CDF~II detector at the Fermilab Tevatron. The masses and decay widths of the mentioned charmed baryon resonances are measured with uncertainties comparable to the world averages for $\Sigma_c$ states, and significantly smaller uncertainties than the world averages for excited $\Lambda_c^+$ states. No hints for any $CP$ violating effects in the resonant substructure of $D^0 \to K_S^0\,\pi^+\,\pi^-$ are found.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Search for the Standard Model Higgs Boson in the Diphoton Final State in $p\bar{p}$ Collisions at $\sqrt{s}$ = 1.96 TeV Using the CDF II Detector

We present a search for the Standard Model Higgs boson decaying into a pair of photons produced in p$p\bar{p}$ collisions with a center of mass energy of 1.96 TeV. The results are based on data corresponding to an integrated luminosity of 10 fb -1 collected by the CDF II detector. Higgs boson candidate events are identified by reconstructing two photons in either the central or plug regions of the detector. The acceptance for identifying photons is significantly increased by using a new algorithm designed to reconstruct photons in the central region that have converted to an electron-positron pair. In addition, a new neural network discriminant is employed to improve the identification of non-converting central photons. No evidence for the Higgs boson is observed in the data, and we set an upper limit on the cross section for Higgs boson production multiplied by the H → γγ branching ratio. For a Higgs boson mass of 125 GeV/c 2 , we obtain an observed (expected) limit of 12.2 (10.8) times the Standard Model prediction at the 95% credibility level.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Study of $p\bar{p}$ collisions that contain leptons, a photon, and a $b$-quark using the CDF II Detector

We present a search for anomalous production of the signature lepton + photon + b-quark + missing transverse energy (`γ6ETb) produced in $p\bar{p}$ collisions at √ s = 1.96 TeV using 6.0 fb -1 of data taken with the CDF detector in Run II at the Tevatron. In addition to this signature-based search, we present a closely-related search for top pair production with an additional radiated photon, t$\bar{t}$γ. We find 85 `γ6ETb events versus an expectation of 99.1±9.3 events. High-statistics control samples are used to evaluate a low-energy photon χ 2 cut. Additionally requiring the events to contain at least three jets, have a total transverse energy of 200 GeV, and that the photon candidate passes the χ 2 cut, we observe 30 t$\bar{t}$γ candidate events versus an expectation from non-top Standard Model (SM) sources of 13.0 ± 2.1 Assuming the difference between the observed number and the predicted non-top SM total is due to top production, we measure the tt$\bar{γ}$ cross section to be 0.18 ± 0.08 pb. We also measure the ratio of the t$\bar{t}$γ cross section to the t$\bar{t}$cross section to be 0.024 ± 0.009, which compares well with a SM prediction of 0.024 ± 0.013

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Measurement of the ratio $B(t \to W b)/B(t \to W q)$ in $t\bar{t}$ dilepton channel at CDF

My analysis is based on the number of b-jets found in t¯t events using the dilepton sample with at least 2 jets in the final state. The charged leptons could be either electrons or muons. Tau leptons are not included. We use SecVtx algorithm, based on the reconstruction of a secondary vertex in the event, in order to identify a jet coming from b-quark fragmentation (b-tagging). Due to the high purity of the t¯t signal in dilepton events it is possible to perform a kinematic measurement of the t¯t cross section. Our strategy is to use this result to make prediction on the number of t¯t events. We divide our sample in subsets according to dilepton type (combination of the lepton type), number of jets in the final states and events with zero, one or two tags. The comparison between events and the prediction, given by the sum of the expected t¯t estimate and the background yield, in each subsample is made using a Likelihood function. Our measured value for R is the one which maximizes the Likelihood, i.e. gives the best match between our expectation and the observed data. We measure: p¯p!t¯t = 7.05±0.53stat±0.42lumi , R= 0.86±0.06 (stat+syst) and, in the hypothesis of CKM matrix unitarity with three quark generations, | Vtb | = 0.93 ± 0.03. Our analysis on the p¯p!t¯t was performed independently of the official dilepton analisys on the t¯t production cross section. So it represents also a valuable crosscheck for the official analysis. In chapter 1, a brief introduction to the theoretical framework is given. The standard model of elementary particles and the Quantum Cromodynamic theories are introduced. Then the top quark is presented, with a short descpription of its properties, as its mass, its production mode and its cross section. Some previous results on R are listed as well. Later we present the experiment that collected our data, both the collider (chapter 2) and the detector (CDF)(chapter 3). In chapter 4 we describe the physics object reconstruction, so how we collect the detector signals and translate those into physical particles traversing our detector. The event selection is described in chapter 5, where we report the complete list of the selection requirements and we estimate our sample composition. In chapters 6 and 7 we report our results for the t¯t production cross section and R. An indirect measurement for |Vtb| is given as well.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Measurement of the $W+$ jets differential cross-sections in $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV using the CDF II Detector

In this thesis the measurements of differential cross sections for the production of the $W$-boson in association with jets in $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV are presented. The measurements are based on 9.0 fb$^{-1}$ of CDF Run II data (i.e., the full dataset). Only events in which the W-boson decays leptonically (i.e., W → ev and W → μv)and at least one jet is present are considered. The lepton candidates are required to have a transverse energy $E^{\ell}_T > 25$GeV and pseudorapidity in the range |n ℓ | < 1 whereas, the jets are reconstructed using the JETCLU algorithm with a radius of 0.4 requiring transverse energy $E^{jet}_T > 25$GeV and pseudorapidity in the range |η jet| < 2. The reconstructed W-boson transverse mass should be greater than 40GeV/c 2 . The differential cross sections as a function of the jet multiplicity ($N$ > or = to 1, 2, 3, 4) and the leading jet transverse energy, are measured separately for each decay channel and then combined. For a meaningful comparison with theory the measured cross-sections are unfolded to remove detector effects. The resulting particle-level cross-sections are compared to theoretical predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Approaching the CDF Top Quark Mass Legacy Measurement in the Lepton+Jets channel with the Matrix Element Method

The discovery of the bottom quark in 1977 at the Tevatron Collider triggered the search for its partner in the third fermion isospin doublet, the top quark, which was discovered 18 years later in 1995 by the CDF and D=0 experiments during the Tevatron Run I. By 1990, intensive efforts by many groups at several accelerators had lifted to over 90 GeV=c2 the lower mass limit, such that since then the Tevatron became the only accelerator with high-enough energy to possibly discover this amazingly massive quark. After its discovery, the determination of top quark properties has been one of the main goals of the Fermilab Tevatron Collider, and more recently also of the Large Hadron Collider (LHC) at CERN. Since the mass value plays an important role in a large number of theoretical calculations on fundamental processes, improving the accuracy of its measurement has been at any time a goal of utmost importance. The present thesis describes in detail the contributions given by the candidate to the massive preparation work needed to make the new analysis possible, during her 8 months long stay at Fermilab.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Search for a Standard Model Higgs Boson in the Channel $VH\to VWW$ with Leptons and Hadronic $\tau$ in the Full CDF Run II Data Set

We present the results of the CDF search for a Standard Model Higgs boson decaying into a pair of W bosons with electrons, muons and hadronically decaying taus in the final state. In particular, we investigate a channel with three objects, two leptons and a tau. In 9.7 fb -1 of data we expect 40.0 ± 5.4 background events and 0.54 ± 0.05 signal events for a Higgs mass hypothesis of 160 GeV/c 2 , whereas in data we count 28 events. We set a 95% C.L. upper limit on σ/σSM of 12.6 for a Higgs mass hypothesis of 160 GeV/c 2 . The expected 95% C.L. upper limit for the same mass is 12.4. Results for other ninete 0 GeV/c2 to 200 GeV/c 2 are also presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Development of a multivariate tool to reject background in a WZ diboson search for the CDF experiment

In the frame of the strong on-going data analysis effort of the CDF collaboration at Fermilab, a method was developed by the candidate to improve the background rejection efficiency in the search for associated pair production of electroweak W, Z bosons. The performaces of the method for vetoing the tt background in a WZ/ZZ → fνq$\bar{q}$ diboson search are reported. The method was developed in the inclusive 2-jets sample and applied to the “tag-2 jets" region, the subsample defined by the request that the two jets carry beauty flavor. In this region the tt production is one of the largest backgrounds. The tt veto proceeds in two steps: first, a set of pre-selection cuts are applied in a candidate sample where up to two leptons are accepted in addition to a jet pair, and the ZZ component of the signal is thus preserved; next, a Neural Network is trained to indicate the probability that the event be top-pair production. To validate the the method as developed in the inclusive 2-jets sample, it is applied to veto region providing a significant rejection of this important background.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Search for $W'\to t b $ in Events with Large Missing Transverse Energy and Jets with the CDF detector at the Fermilab Tevatron Collider

In the scope of the strong ongoing data analysis efforts of the CDF col- laboration at Fermilab, we present a search for the production of mas sive W1 bosons decaying to a top and a bottom quark in p$\bar{p}$ collisions at √s = 1.96 TeV. To perform this search, we select events with large Missing Transverse Energy plus two or three jets, in which the W generated from top decays leptonically, and either the e or µ is lost or the τ is reconstructed as a jet. A complete study of the selected sample is discussed, including the creation and subsequent optimization of a Neural Network-based multivariate tool to reject the QCD multijet background from the signal region. Finally, we perform a likelihood-based multichannel Bayesian fit procedure on the invariant transverse mass of the Missing Transverse Energy and jets to extract 95% CL limits on σ(p$\bar{p}$ . → W') × B(W' → tb) for M W' = 200 GeV/c 2

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

First Observation of Charmed Resonances in the $\Lambda^0_b \to \Lambda^+_c \pi^- \pi^+ \pi^-$ Inclusive Decay and Measurement of Their Relative Branching Ratios at CDF

We present the observation of the $\Lambda^0_b$ decay into a $\Lambda^+_c \pi^- \pi^+ \pi^-$ final state, in $p\bar{p}$ collisions at $\sqrt{s}$ = 1:96 TeV. The data analyzed were collected by the CDF II detector at the Fermilab Tevatron collider, and correspond to 2:4 $fb^{-1}$ of integrated luminosity. We fit the invariant mass distribution of the reconstructed candidates to extract a signal yield of 848 $\pm$ 93 $\Lambda^0_b$ into $\Lambda^+_c \pi^- \pi^+ \pi^-$....

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Search for resonances in $b$-jets final states with the CDF II and the LHCb experiments

This thesis describes the search for resonances decaying into a pair of b-jets performed with the datasets collected by the CDF II experiment at the Tevatron and the LHCb at the LHC. The unique characteristics of these particle detectors, which are highlighted through the thesis with a constant comparison between the two experiments, give the opportunity to search also in the low dijet invariant mass region, unaccessible to the other general purpose detectors at the LHC. A dataset corresponding to 5:4 fb

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Measurement of initial state radiation using Drell-Yan Events at CDF

A study of the initial state gluon radiation (ISR) measurement in proton-antiproton collisions at $\sqrt{s}$ = 1.96 TeV is presented. This analysis uses Drell-Yan ($Z/\gamma^* \to ee,\mu\mu$) events in the CDF data sample, corresponding to an integrated luminosity of 9.4 $\mathrm{fb^{-1}}$. We find that the mean value of the transverse momentum distribution of the Drell-Yan system ($\langle p_T^{DY} \rangle$) is a good observable to measure the effect of the ISR. This observable has a logarithmic dependence on the mass square of $Z/\gamma^*$ boson ($m^2_{DY}$), which is parameterized as a linear function of $\langle p_T^{DY} \rangle = (-7.57 \pm 0.69) + (2.15 \mp 0.08)\log m^2_{DY}$. This measurement provides a way to estimate the effect of softly evolving ISR at very high mass region, and it can be used to control the ISR effect in other physics processes.

Seo, Hyon San↗
DOE OSTI2012

Photon measurements with the full CDF data set

We present results of the cross section measurement of photon production associated with bottom- and charm-quark production and of the cross section measurement for diphoton production. The measurements involve the full CDF data sample and they are compared with state-of-the-art calculations. The comparisons show only partial agreement between data and calculations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

THE CDF ARCHIVE: HERSCHEL PACS AND SPIRE SPECTROSCOPIC DATA PIPELINE AND PRODUCTS FOR PROTOSTARS AND YOUNG STELLAR OBJECTS

We present the COPS-DIGIT-FOOSH (CDF) Herschel spectroscopy data product archive, and related ancillary data products, along with data fidelity assessments, and a user-created archive in collaboration with the Herschel-PACS and SPIRE ICC groups. Our products include datacubes, contour maps, automated line fitting results, and best 1D spectra products for all protostellar and disk sources observed with PACS in RangeScan mode for two observing programs: the DIGIT Open Time Key Program (KPOT-nevans-1 and SDP-nevans-1; PI: N. Evans), and the FOOSH Open Time Program (OT1-jgreen02-2; PI: J. Green). In addition, we provide our best SPIRE-FTS spectroscopic products for the COPS Open Time Program (OT2-jgreen02-6; PI: J. Green) and FOOSH sources. We include details of data processing, descriptions of output products, and tests of their reliability for user applications. We identify the parts of the data set to be used with caution. The resulting absolute flux calibration has improved in almost all cases. Compared to previous reductions, the resulting rotational temperatures and numbers of CO molecules have changed substantially in some sources. On average, however, the rotational temperatures have not changed substantially (<2%), but the number of warm (T{sub rot} ∼ 300 K) CO molecules has increased by about 18%.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1988

Common Data Format (CDF) to store images

The original goal of this study was to allow free interchange of images between the HGS and other analytical tools available to NASA. Originally conceived as a collection of individual computer programs that could individually convert any format image to any other format and transfer images via several routes, NASA elected to adopt a Common Data Format (CDF) to store images. This allowed the storage of all images in one format on the NASA EADS. Most of the individual programs were then combined and placed in a user friendly menu-driven system that allows free interchange of image formats within EADS (Sun Workstation), HGS, and Omnicon systems. Additional software and hardware was supplied that allows physical transfer of the formatted images throughout these systems and to external systems.

Shreve, Loy W., II↗
DOE OSTI2010

Combination of Standard Model Higgs searches at CDF

We present the latest combination of searches for a standard model (SM) Higgs boson in p{bar p} collisions at {radical}s = 1.96 TeV recorded by the CDF II detector at the Fermilab Tevatron. Using data corresponding to 2.3-5.9 fb{sup -1} of integrated luminosity, we perform searches in a number of different production and decay modes and then combine them to improve sensitivity. No excess in data above that expected from backgrounds is observed; therefore, we set upper limits on the production cross section times branching fraction as a function of the SM Higgs boson mass (m{sub H}). The combined observed (expected) limit is 1.9 (1.8) times the SM prediction at m{sub H} =115 GeV/c{sup 2} and 1.0 (1.1) times the SM prediction at m{sub H} = 165 GeV/c{sup 2}.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗