We present a measurement of the $W$-boson-pair production cross section in $pbar{p}$ collisions at 1.96 TeV center-of-mass energy and the first measurement of the differential cross section as a function of jet multiplicity and leading-jet energy. Th
e $W^{+}W^{-}$ cross section is measured in the final state comprising two charged leptons and neutrinos, where either charged lepton can be an electron or a muon. Using data collected by the CDF experiment corresponding to $9.7~rm{fb}^{-1}$ of integrated luminosity, a total of $3027$ collision events consistent with $W^{+}W^{-}$ production are observed with an estimated background contribution of $1790pm190$ events. The measured total cross section is $sigma(pbar{p} rightarrow W^{+}W^{-}) = 14.0 pm 0.6~(rm{stat})^{+1.2}_{-1.0}~(rm{syst})pm0.8~(rm{lumi})$ pb, consistent with the standard model prediction.
We present a measurement of the top-quark mass in events containing two leptons (electrons or muons) with a large transverse momentum, two or more energetic jets, and a transverse-momentum imbalance. We use the full proton-antiproton collision data s
et collected by the CDF experiment during the Fermilab Tevatron Run~II at center-of-mass energy $sqrt{s} = 1.96$ TeV, corresponding to an integrated luminosity of 9.1 fb$^{-1}$. A special observable is exploited for an optimal reduction of the dominant systematic uncertainty, associated with the knowledge of the absolute energy of the hadronic jets. The distribution of this observable in the selected events is compared to simulated distributions of ${tbar{t}}$ dilepton signal and background.We measure a value for the top-quark mass of $171.5pm 1.9~{rm (stat)}pm 2.5~{rm (syst)}$ GeV/$c^2$.
We measure the particle-level forward-backward production asymmetry in $bbar{b}$ pairs with masses $m(bbar{b})$ larger than 150 GeV/$c^2$, using events with hadronic jets and employing jet charge to distinguish $b$ from $bar{b}$. The measurement uses
9.5/fb of ppbar collisions at a center of mass energy of 1.96 TeV recorded by the CDF II detector. The asymmetry as a function of $m(bbar{b})$ is consistent with zero, as well as with the predictions of the standard model. The measurement disfavors a simple model including an axigluon with a mass of 200 GeV/$c^2$ whereas a model containing a heavier 345 GeV/$c^2$ axigluon is not excluded.
We report on a search for charged massive resonances decaying to top ($t$) and bottom ($b$) quarks in the full data set of proton-antiproton collisions at center-of-mass energy of $sqrt{s} = 1.96$ TeV collected by the CDF~II detector at the Tevatron,
corresponding to an integrated luminosity of 9.5 $fb^{-1}$. No significant excess above the standard model (SM) background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged particle production cross section times branching ratio to $t b$. Using a SM extension with a $W^{prime}$ and left-right-symmetric couplings as a benchmark model, we constrain the $W^{prime}$ mass and couplings in the 300 to 900 GeV/$c^2$ range. The limits presented here are the most stringent for a charged resonance with mass in the range 300 -- 600 GeV/$c^2$ decaying to top and bottom quarks.
We measure exclusive $pi^+pi^-$ production in proton-antiproton collisions at center-of-mass energies $sqrt{s}$ = 0.9 and 1.96 TeV in the Collider Detector at Fermilab. We select events with two oppositely charged particles, assumed to be pions, with
pseudorapidity $|eta| < 1.3$ and with no other particles detected in $|eta| < 5.9$. We require the $pi^+pi^-$ system to have rapidity $|y|<$ 1.0. The production mechanism of these events is expected to be dominated by double pomeron exchange, which constrains the quantum numbers of the central state. The data are potentially valuable for isoscalar meson spectroscopy and for understanding the pomeron in a region of transition between nonperturbative and perturbative quantum chromodynamics. The data extend up to dipion mass $M(pi^+pi^-)$ = 5000 MeV/$c^2$ and show resonance structures attributed to $f_0$ and $f_2(1270)$ mesons. From the $pi^+pi^-$ and $K^+K^-$ spectra, we place upper limits on exclusive $chi_{c0}(3415)$ production.
We report a measurement of the indirect CP-violating asymmetries ($A_{Gamma}$) between effective lifetimes of anticharm and charm mesons reconstructed in $D^0to K^+ K^-$ and $D^0to pi^+pi^-$ decays. We use the full data set of proton-antiproton colli
sions collected by the Collider Detector at Fermilab experiment and corresponding to $9.7$~fb$^{-1}$ of integrated luminosity. The strong-interaction decay $D^{*+}to D^0pi^+$ is used to identify the meson at production as $D^0$ or $overline{D}^0$. We statistically subtract $D^0$ and $overline{D}^0$ mesons originating from $b$-hadron decays and measure the yield asymmetry between anticharm and charm decays as a function of decay time. We measure $A_Gamma (K^+K^-) = (-0.19 pm 0.15 (stat) pm 0.04 (syst))%$ and $A_Gamma (pi^+pi^-)= (-0.01 pm 0.18 (stat) pm 0.03 (syst))%$. The results are consistent with the hypothesis of CP symmetry and their combination yields $A_Gamma = (-0.12 pm 0.12)%$.
An updated measurement of the single top quark production cross section is presented using the full data set collected by the Collider Detector at Fermilab (CDF) and corresponding to 9.5 fb${}^{-1}$ of integrated luminosity from proton-antiproton col
lisions at 1.96 TeV center-of-mass energy. The events selected contain an imbalance in the total transverse energy, jets identified as originating from $b$ quarks, and no identified leptons. The sum of the $s$- and $t$-channel single top quark cross sections is measured to be $3.53_{-1.16}^{+1.25}$ pb and a lower limit on $V_{tb}$ of 0.63 is obtained at the 95% credibility level. These measurements are combined with previously reported CDF results obtained from events with an imbalance in total transverse energy, jets identified as originating from $b$ quarks, and exactly one identified lepton. The combined cross section is measured to be $3.02_{-0.48}^{+0.49}$ pb and a lower limit on $V{tb}$ of 0.84 is obtained at the 95% credibility level.
The top-quark mass M_top is measured using top quark-antiquark pairs produced in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV and decaying into a fully hadronic final state. The full data set collected with the CDFII detector a
t the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 9.3 fb-1, is used. Events are selected that have six to eight jets, at least one of which is identified as having originated from a b quark. In addition, a multivariate algorithm, containing multiple kinematic variables as inputs, is used to discriminate signal events from background events due to QCD multijet production. Templates for the reconstructed top-quark mass are combined in a likelihood fit to measure M_top with a simultaneous calibration of the jet-energy scale. A value of M_top = 175.07+- 1.19(stat)+1.55-1.58(syst) GeV/c^2 is obtained for the top-quark mass.
Differential cross sections for the production of $Z$ bosons or off-shell photons $gamma^*$ in association with jets are measured in proton-antiproton collisions at center-of-mass energy $sqrt{s}=1.96$ TeV using the full data set collected with the C
ollider Detector at Fermilab in Tevatron Run II, and corresponding to 9.6 fb$^{-1}$ of integrated luminosity. Results include first measurements at CDF of differential cross sections in events with a $Z/gamma^*$ boson and three or more jets, the inclusive cross section for production of $Z/gamma^*$ and four or more jets, and cross sections as functions of various angular observables in lower jet-multiplicity final states. Measured cross sections are compared to several theoretical predictions.
We report a measurement of single top quark production in proton-antiproton collisions at a center-of-mass energy of sqrt{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 to Wb to l{ u}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 3.04+0.57-0.53 pb and set a lower limit on the magnitude of the coupling between the top quark and bottom quark |Vtb| > 0.78 at the 95% credibility level.
