Simulations from a new neutrino event generator

We construct a new Monte Carlo generator of events for neutrino interactions. The dynamical models for quasi-elastic reactions, $\Delta$ excitation and more inelastic events described by the DIS formalism with the PDFs modified according to recent JLab data are used. We describe in detail single pion production channels, which combine the $\Delta$ excitation and DIS contribution. Many comparisons of the outcome of simulations with experimental data are presented.Comment: To appear in the proceedings of 4th International Workshop on Neutrino Nucleus Interactions in the Few GeV Region (NuInt05), Okayama, Japan, 26-29 September, 200

Measurement of the production of a W boson in association with a charm quark in pp collisions at sqrt(s)=7 TeV with the ATLAS detector

The production of a W boson in association with a single charm quark is studied using 4.6 fb^-1 of pp collision data at sqrt(s)=7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96 +0.26 -0.30 at Q^2=1.9 GeV^2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio sigma(W^+ + bar{c})/sigma(W^- + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s-bar{s} quark asymmetry.Fil: ATLAS Collaboration, G. AAd, F. Monticelli, et al. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Cern - European Organization For Nuclear Research; Suiz

Measurement of the parity-violating asymmetry parameter αb and the helicity amplitudes for the decay Λ0b→J/ψ+Λ0 with the ATLAS detector

A measurement of the parity-violating decay asymmetry parameter, αb, and the helicity amplitudes for the decay Λb0→J/ψ(μ+μ-)Λ0(pπ-) is reported. The analysis is based on 1400 Λb0 and Λ¯b0 baryons selected in 4.6  fb-1 of proton-proton collision data with a center-of-mass energy of 7 TeV recorded by the ATLAS experiment at the LHC. By combining the Λb0 and Λ¯b0 samples under the assumption of CP conservation, the value of αb is measured to be 0.30±0.16(stat)±0.06(syst). This measurement provides a test of theoretical models based on perturbative QCD or heavy-quark effective theory.Fil: F. Monticelli.Fil: Atlas Collaboration

Z boson production in p+Pb collisions at sNN√=5.02 TeV measured with the ATLAS detector

The ATLAS Collaboration has measured the inclusive production of Z bosons via their decays into electron and muon pairs in p+Pb collisions at √ sNN = 5.02 TeV at the Large Hadron Collider. The measurements are made using data corresponding to integrated luminosities of 29.4 nb−1 and 28.1 nb−1 for Z → ee and Z → µµ, respectively. The results from the two channels are consistent and combined to obtain a cross section times the Z → `` branching ratio, integrated over the rapidity region |y ∗ Z | < 3.5, of 139.8 ± 4.8 (stat.) ± 6.2 (syst.) ± 3.8 (lumi.) nb. Differential cross sections are presented as functions of the Z boson rapidity and transverse momentum, and compared with models based on parton distributions both with and without nuclear corrections. The centrality dependence of Z boson production in p+Pb collisions is measured and analyzed within the framework of a standard Glauber model and the model’s extension for fluctuations of the underlying nucleon-nucleon scattering cross sectionFil: Aad, G.. Aix-Marseille Université; FranciaFil: Abbott, B.. Oklahoma State University; Estados UnidosFil: Abdallah, J.. Academia Sinica; ChinaFil: Abdinov, O.. Azerbaijan Academy of Sciences; AzerbaiyánFil: Aben, R.. University of Amsterdam; Países BajosFil: Alconada Verzini, María Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Alonso, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Arduh, Francisco Anuar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Dova, Maria Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Monticelli, Fernando Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Wahlberg, Hernan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Otero y Garzon, Gustavo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Piegaia, Ricardo Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Reisin, Hernan Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Sacerdoti, Sabrina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Zieminska, D.. Indiana University; Estados UnidosFil: Zimine, N. I.. Joint Institute for Nuclear Research ; RusiaFil: Zimmermann, C.. Universität Mainz; AlemaniaFil: Zimmermann, S.. Albert-Ludwigs-Universität; AlemaniaFil: Zinonos, Z.. Georg-August-Universität; AlemaniaFil: Zinser, M.. Universität Mainz; AlemaniaFil: Ziolkowski, M.. Universität Siegen ; AlemaniaFil: Živković, L.. University of Belgrade; SerbiaFil: Zobernig, G.. University of Wisconsin; Estados UnidosFil: Zoccoli, A.. Università di Bologna; ItaliaFil: Nedden, M. zur. Humboldt University; AlemaniaFil: Zurzolo, G.. Università di Napoli; ItaliaFil: Zwalinski, L.. Cern - European Organization For Nuclear Research; SuizaFil: The ATLAS Collaboration. No especifica

Triggers for displaced decays of long-lived neutral particles in the ATLAS detector

A set of three dedicated triggers designed to detect long-lived neutral particles decaying throughout the ATLAS detector to a pair of hadronic jets is described. The efficiencies of the triggers for selecting displaced decays as a function of the decay position are presented for simulated events. The effect of pile-up interactions on the trigger efficiencies and the dependence of the trigger rate on instantaneous luminosity during the 2012 data-taking period at the LHC are discussedFil: Aad, G.. Albert Ludwigs Universität; AlemaniaFil: Abajyan, T.. Universitaet Bonn; AlemaniaFil: Abbott, B.. University of Oklahoma; Estados UnidosFil: Abdallah, J.. Universitat Autònoma de Barcelona; EspañaFil: Abdel Khalek, S.. Universite Paris Sud; FranciaFil: Alconada Verzini, María Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Alonso, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Anduaga, Xabier Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Dova, Maria Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: González Silva, María Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Monticelli, Fernando Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Otero y Garzon, Gustavo Javier. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Piegaia, Ricardo Nestor. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Romeo, Gaston Leonardo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tripiana, Martin Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Zhuang, X.. Ludwig Maximilians Universitat; AlemaniaFil: Zhuravlov, V.. Max-Planck Institut für Physik; AlemaniaFil: Zieminska, D.. Indiana University; Estados UnidosFil: Zimin, N. I.. Joint Institute for Nuclear Research; RusiaFil: Zimmermann, R.. Universitaet Bonn; AlemaniaFil: Zimmermann, S.. Universitaet Bonn; AlemaniaFil: Zimmermann, S.. Albert Ludwigs Universität; AlemaniaFil: Ziolkowski, M.. Universität Siegen; AlemaniaFil: Zitoun, R.. Université de Savoie; FranciaFil: Živković, L.. Columbia University; Estados UnidosFil: Zmouchko, V. V.. State Research Center Institute for High Energy Physics; RusiaFil: Zobernig, G.. University of Wisconsin; Estados UnidosFil: Zoccoli, A.. Università di Bologna; ItaliaFil: zur Nedden, M.. Humboldt University; AlemaniaFil: Zutshi, V.. Northern Illinois University; Estados Unido

Measurement of the ppbar to ttbar production cross section at sqrt(s)=1.96 TeV in the fully hadronic decay channel

A measurement of the top quark pair production cross section in proton anti-proton collisions at an interaction energy of sqrt(s)=1.96 TeV is presented. This analysis uses 405 pb-1 of data collected with the D0 detector at the Fermilab Tevatron Collider. Fully hadronic ttbar decays with final states of six or more jets are separated from the multijet background using secondary vertex tagging and a neural network. The ttbar cross section is measured as sigma(ttbar)=4.5 -1.9 +2.0 (stat) -1.1 +1.4 (syst) +/- 0.3 (lumi) pb for a top quark mass of m(t) = 175 GeV/c^2.Comment: 10 pages, 10 figures, submitted to Phys. Rev.

Search for R-parity Violating Supersymmetry in Dimuon and Four-Jets Channel

We present results of a search for R-parity-violating decay of the neutralino chi_1^0, taken to be the Lightest Supersymmetric Particle. It is assumed that this decay proceeds through one of the lepton-number violating couplings lambda-prime_2jk (j=1,2; k=1,2,3). This search is based on 77.5 pb-1 of data, collected by the D0 experiment at the Fermilab Tevatron in ppbar collisions at a center of mass energy of 1.8 TeV in 1992-1995.Comment: 10 pages, 3 figure

Search for Zgamma events with large missing transverse energy in ppbar collisions at sqrt(s)=1.96 TeV

We present the first search for supersymmetry (SUSY) in Zgamma final states with large missing transverse energy using data corresponding to an integrated luminosity of 6.2 fb-1 collected with the D0 experiment in ppbar collisions at sqrt(s)=1.96 TeV. This signature is predicted in gauge-mediated SUSY-breaking models, where the lightest neutralino is the next-to-lightest supersymmetric particle (NLSP) and is produced in pairs, possibly through decay from heavier supersymmetric particles. The NLSP can decay either to a Z boson or a photon and an associated gravitino that escapes detection. We exclude this model at the 95% C.L. for SUSY breaking scales of Lambda < 87 TeV, corresponding to neutralino masses of < 151 GeV.Comment: submitted to Phys. Rev. Let

Measurement of the semileptonic charge asymmetry in B0 meson mixing with the D0 detector

We present a measurement of the semileptonic mixing asymmetry for B0 mesons, a^d_{sl}, using two independent decay channels: B0 -> mu+D-X, with D- -> K+pi-pi-; and B0 -> mu+D*-X, with D*- -> antiD0 pi-, antiD0 -> K+pi- (and charge conjugate processes). We use a data sample corresponding to 10.4 fb^{-1} of ppbar collisions at sqrt(s) = 1.96 TeV, collected with the D0 experiment at the Fermilab Tevatron collider. We extract the charge asymmetries in these two channels as a function of the visible proper decay length (VPDL) of the B0 meson, correct for detector-related asymmetries using data-driven methods, and account for dilution from charge-symmetric processes using Monte Carlo simulation. The final measurement combines four signal VPDL regions for each channel, yielding a^d_{sl} = [0.68 \pm 0.45 \text{(stat.)} \pm 0.14 \text{(syst.)}]%. This is the single most precise measurement of this parameter, with uncertainties smaller than the current world average of B factory measurements.Comment: Version includes minor textual changes following peer review by journal, most notably the updating of Ref. [21] to reflect the most recent publicatio