Abstracts submitted to APS 2009
 Top Properties Measurement of forward-backward asymmetry in top quark production at CDF Speaker: Glenn Strycker (CDF Collaboration) PDF We measure a forward-backward charge asymmetry in the rapidities of top quarks produced in $p\bar p$ collisions at $\sqrt s$=1.96 TeV. The $t\bar t$ kinematics are reconstructed in ~800 lepton+jets events collected in a 3 $fb^{-1}$ exposure with CDF detector at Fermilab. We present two independent techniques -- a model independent unfold and a likelihood fit to a linear asymmetry in the production angle $(1+Acos(\alpha))$ -- that give consistent results for the parton level asymmetry in both the laboratory and $t\bar t$ rest frames. The results are compared to the small charge asymmetry expected in QCD at NLO. Measurement of the top pair production cross section in the dilepton decay channel at CDF Speaker: Chang-Seong Moon (CDF Collaboration) PDF We present a measurement of the $t\bar{t}$ production cross section in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV using 2.8 fb$^{-1}$ of data collected by the CDF detector at the Fermilab Tevatron. We use $t\bar{t}$ dilepton events reconstructed with missing transverse energy and jets assuming top quark mass $m_t$ = 175 GeV/c$^2$. We measure $\sigma_{ t\bar{t}} = 6.13 \pm 0.88_{stat} \pm 0.40_{syst} \pm 0.38_{lumi}$ pb. Measurement of the $W$ boson helicity fractions in $t\overline{t}$ production in dilepton channel at CDF Speaker: Roman Lysak (CDF Collaboration) PDF Abstract: We present a $t\bar{t}$\ production cross section measurement in the multi-jet final state channel from collisions of protons and anti-protons at $\sqrt{s}$= 1.96 TeV at the CDF II Detector at the Fermilab Tevatron. We study events with high missing transverse energy and we select those that contain jets that are identified in the silicon vertex detector as originating from b-quarks using a neural network algorithm. Search for non-standard model top antitop resonance production in the all-hadronic channel at CDF Speaker: Yuri Oksuzian (CDF Collaboration) PDF We present an updated result of a search for resonant top-antitop pair production and subsequent decay in the all-hadronic channel. We examine the top-antitop invariant mass spectrum observed in CDF data from 1.96 TeV $p\overline p$ collisions at the Fermilab Tevatron. We apply a powerful reconstruction technique where the observed event kinematics are constrained according to the full standard model top-antitop production and decay matrix element. This technique provides excellent mass resolution. Also, probability densities from the per-event matrix element calculation are used as discriminants to reduce and control the large backgrounds of the all-hadronic channel. Single Top Measurement of the single top cross section Speaker: Bruno Casal (CDF Collaboration) PDF We present recent results from searches for single-top-quark production and single-top polarization studies using 3.2 $fb^{-1}$ of data accumulated with the CDF detector at the Fermilab Tevatron. We select events with one charged lepton, large missing transverse energy, and two or three jets, where at least one jet is identified as a b-quark jet using displaced secondary-vertex information from the CDF silicon detector. We employ a boosted decision tree analysis technique and a neural-network jet-flavor separator to improve separation of signal and background and greatly improve the sensitivity of our search. Measurement of the single top production cross section in the transverse missing energy plus jets sample Speaker: Karolos Potamianos (CDF Collaboration) PDF Standard model top quarks are produced mostly in pairs at the Tevatron through the strong force. However, the production of a single top quark per process is allowed through electroweak processes. We present a measurement of the the standard model single top production cross-section in proton-anti protons collisions at 1.96 TeV center of mass energy. The data collected with the CDF II detector at the Tevatron collider at Fermilab correspond to an integrated luminosity of 2.1 $fb^{-1}$. Until now, Tevatron experiments searched for single top only in events where one high energy electron or muon has been identi?ed, to suppress the huge QCD background. Here, we look for the first time at events where no electron or muon has been identi?ed, and where tau leptons decay hadronically and are reconstructed as jets in the calorimeter. Thus, we consider a signature of two b-jets, no leptons, and missing transverse energy. We present preliminary results as well as ongoing efforts in this search. Measurement of the polarization of singly-produced top quarks in CDF Speaker: Ji-Eun Jung (CDF collaboration) PDF We present a measurement of the polarization of singly-produced top quarks in $p\bar p$ collisions using 3 $fb^{-1}$ of data collected with the CDF detector. Single top quarks are expected to be produced via virtual $W$ boson exchange in $t$-channel and $s$-channel processes. The standard model predicts a left-handed vector coupling at the $Wtb$ vertex, but extensions allow a right-handed vector coupling. We measure separately the left- and right-handed couplings, and thus the polarization, by measuring the angular distributions of the top quark's decay products. Top Mass Measurement of the top quark mass using quantities that are independent of the jet energy scale at CDF Speaker: Ford Garberson (CDF collaboration) PDF We will present two techniques for measuring the top quark mass in the lepton plus jets channel using quantities independent of the jet energy scale uncertainty. One technique exploits the correlation of the transverse decay length of $b$-tagged jets with the top mass, and the other exploits the correlation of the transverse momentum of the lepton in the same events with the top mass. While these results are still statistically limited, their precision will improve with added data at the Teva tron and the LHC. Further, since their correlation to more conventional top mass measurement techniques is small, they will help to reduce the overall uncertainty on the top mass in combination with other results. Top quark mass measurement in the lepton+jets and dilepton channels at CDF using mT2 Speaker: Jian Tang (CDF Collaboration) PDF A measurement of top quark mass at CDF will be presented using a 3.0 $fb^{-1}$ data sample in both lepton+jets and dilepton channels. In the lepton+jets channel, we determine the reconstructed top quark mass by minimizing the $\chi^{2}$ for the overconstrained kinematic system, and we also measure the hadronically decaying $W$ boson mass to provide an $in-situ$ improvement in the determination of jet energy scale. In the dilepton channel, we replace our old observable $H_T$, which is the scalar sum of transverse energy of all particles in one event, with a new observable $m_T^2$, which is used in $W$ mass measurements and SUSY searches. We find a satisfying improvement in our result of top quark mass measurement using this new observable. Measurement of the top quark mass in the lepton+track sample at CDF Speaker: Marco Trovato (CDF Collaboration) PDF We report on a measurement of the top quark mass in the lepton+track sample of events at CDF. This new selection was applied to $t\bar t$ candidates in the dilepton channel in order to increase the acceptance by relaxing the cuts on one lepton. To constrain the event kinematics the azimuthal angles of the two neutrinos are assumed as known and the top quark mass is reconstructed accordingly. The full neutrino phase space is scanned and $\chi^2$-dependent weights are given to the solutions in order to build a preferred mass for each event. The integrated luminosity of the data sample is 2.9 fb$^{-1}$. 328 candidate events were reconstructed and fitted as a superposition of signal and background. In a constrained fit with 145.0 $\pm$ 17.3 background events as determined in the production cross section studies we measure $m_t$= 165.5 $\pm^{3.4}_{3.3}$ (stat) $\pm$ 3.1 (syst.) GeV/c$^2$. A matrix element analysis measurement of the top quark mass in the lepton + jets channel with an in situ jet energy scale measurement Speaker: Daryl Hare (CDF Collaboration) PDF We measure the top quark mass from $p\bar p$ collisions at 1.96 TeV at CDF in the lepton + jets channel with at least 3 $fb^{-1}$ of data. Events require a single lepton, missing transverse energy, and 4 jets of which at least one must be tagged as a b jet. We use a 2D unbinned likelihood fit based on per-event probabilities calculated from leading-order signal ($t\bar t$) and background ($W$+jets) matrix elements. Our measurement is dependent upon the energy scale of calorimeter jets, so we measure this scale in-situ by constraining the invariant mass of the two jets from to the W boson mass.