Top Quark Mass Measurements

Preliminary results on the measurement of the top quark mass (mt) at the Tevatron Collider are presented. In the dilepton decay channel, the CDF Collaboration measures mt=175.0(+17.4)(-16.9)(stat.)+/-8.4(syst.) GeV/c2, using a sample of ~126 pb-1 of proton-antiproton collision data at sqrt(s)=1.96 TeV (Run II). In the lepton plus jets channel, the CDF Collaboration measures 177.5(+12.7)(-9.4)(stat.)+/-7.1(syst.) GeV/c2, using a sample of ~102 pb-1 at sqrt(s)=1.96 TeV. The D0 Collaboration has newly applied a likelihood technique to improve the analysis of ~125 pb-1 of proton-antiproton collisions at sqrt(s)=1.8 TeV (Run I), with the result: mt=180.1+/-3.6(stat.)+/-3.9(syst.) GeV/c2. The latter is combined with all the measurements based on the data collected in Run I to yield the most recent and comprehensive experimental determination of the top quark mass: mt=178.0+/-2.7(stat.)+/-3.3(syst.) GeV/c2Comment: Contribution to the proceedings of the XXXIXth Rencontres de Moriond, "QCD and High Energy Hadronic Interactions", March 200

Measurements of the Top Quark at the Tevatron Collider

We present recent preliminary measurements of the top-antitop pair production cross section and determinations of the top quark pole mass, performed using the data collected by the CDF and D0 Collaborations at the Tevatron Collider. In the lepton plus jets final state, with semileptonic B decay, the pair production cross section has now been measured at CDF using 760 pb^{-1} of proton-antiproton collisions at a centre-of-mass energy of \sqrt{s}=1.96 TeV. A measurement of the production cross section has also been made with 1 fb^{-1} of data in the all-jets final state by the CDF Collaboration. The mass of the top quark has now been measured using 1 fb^{-1} of collision data using all decay channels of the top quark pair, yielding the most precise measurements of the top mass to date.Comment: Contribution to the proceedings of the "Heavy Quarks and Leptons" conference, Munich, 2006; reference [2] adde

Discriminating Z' signals in semileptonic top pair production at the LHC

We investigate the sensitivity of top pair production to the properties of different Beyond the Standard Model theories embedding a new neutral boson. We include six-fermion decay, and account for the full tree-level Standard Model ttbar interference, with all intermediate particles allowed off-shell. We focus on those observables best suited to the lepton-plus-jets final state at the LHC, and simulate the resulting experimental conditions, including kinematic requirements and top quark pair reconstruction in the presence of missing transverse energy and combinatorial ambiguity in quark-top assignment. In particular, we demonstrate the use of asymmetry observables to probe the coupling structure of a new neutral resonance, in addition to cases in which these asymmetries may even form complementary discovery observables in combination with the differential cross section.Comment: 4 pages, 1 figure, 1 table. arXiv admin note: substantial text overlap with arXiv:1610.0407

Using asymmetry observables to discover and distinguish Z' signals in top pair production with the lepton-plus-jets final state at the LHC

We study the sensitivity of top pair production with six-fermion decay at the LHC to the presence and nature of an underlying Z' boson, accounting for full tree-level Standard Model ttbar interference, with all intermediate particles allowed off-shell. We concentrate on the lepton-plus-jets final state and simulate experimental conditions, including kinematic requirements and top quark pair reconstruction in the presence of missing transverse energy and combinatorial ambiguity in jet-top assignment. We focus on the differential mass spectra of the cross section and asymmetry observables, especially demonstrating the use of the latter in probing the coupling structure of a new neutral resonance, in addition to cases in which the asymmetry forms a complementary discovery observable.Comment: 4 pages, proceedings contribution for Fourth Annual Large Hadron Collider Physics, 13-18 June 2016, Lund, Swede

Measurements of vector boson plus jets at the Tevatron

We present preliminary measurements of Z/γ∗+jets, W + c and Z + b + X at the Tevatron, and review recent measurements of vector boson plus inclusive and heavy-flavor jets production. All measurements are in agreement with next-to-leading-order QCD calculations within the experimental and theoretical uncertainties. We also point to comparisons of the production rate and kinematics of the data with several Monte Carlo simulation programs of vector boson + jets processes

A linear axiomatization of negation as failure

AbstractThis paper is concerned with the axiomatization of success and failure in propositional logic programming. It deals with the actual implementation of SLDNF in PROLOG, as opposed to the general nondeterministic SLDNF evaluation method. Given any propositional program P, a linear theory LTP is defined (the linear translation of P) and the following results are proved for any literal A: soundness of PROLOG evaluation (if the goal A PROLOG-succeeds on P, then LTP⊢lin A, and if A PROLOG-fails on P, then LTP⊢lin A⊥), and completeness of PROLOG evaluation (if LTP⊢lin A, then the goal A PROLOG-succeeds on P, and if LTP⊢lin A⊥, then A PROLOG-fails on P). Here ⊢lin means provability in linear logic, and A⊥ is the linear negation of A

The forward-backward asymmetry of top quark production at the Tevatron in warped extra dimensional models

The CDF and D0 experiments have reported on the measurement of the forward-backward asymmetry of top quark pair production at the Tevatron and the result is that it is more than 2 standard deviations above the predicted value in the Standard Model. This has to be added to the longstanding anomaly in the forward-backward asymmetry for bottom quark production at LEP which is 3 standard deviations different from the Standard Model value. The discrepancy in the bottom asymmetry can be accounted for by the contributions of Kaluza-Klein excitations of electroweak gauge bosons at LEP in warped extra dimensional models in which the fermions are localized differently along the extra dimension so that the gauge interactions of heavy third generation fermions are naturally different from that of light fermions. In this paper, we show that it is more difficult to elaborate a model generating a significant top asymmetry in a similar way -- through exchanges of Kaluza-Klein gluons at the Tevatron -- due to the indirect constraints originating from precision electroweak data.Comment: 4 pages, 1 figure, published versio