Combination of CDF and D0 Measurements of the W boson Helicity in Top Quark Decays

We report the combination of recent measurements of the helicity of the W boson from top quark decay by the CDF and D0 collaborations, based on data samples corresponding to integrated luminosities of the 2.7-5.4 fb-1 of pp- collisions collected during Run II of the Fermilab Tevatron collider. Combining measurements that simultaneously determine the fractions of the W bosons with longitudinal (f0) and right-handed (f+) helicities, we find f0= 0.722 ± 0.081[±0.062(stat) ± 0.052(syst)] and f+ = -0.033 ± 0.046[±0.034(stat) ± 0.031(syst)]. Combining measurements where one of the helicity fractions is fixed to the value expected in the standard model, we find f0 = 0.682 ± 0.057[±0.035(stat) ± 0.046(syst)] for fixed f+ and f+ = -0.015 ± 0.035[±0.018(stat) ± 0.030(syst)] for fixed f0. The results are consistent with standard model expectations.We thank the staffs at Fermilab and collaborating institutions, and acknowledge support from the DOE and NSF (USA); CEA and CNRS/IN2P3 (France); FASI, Rosatom and RFBR (Russia); CNPq, FAPERJ, FAPESP, and FUNDUNESP (Brazil); DAE and DST (India); INFN (Italy); Ministry of Education, Culture, Sports, Science, and Technology (Japan); Colciencias (Colombia); CONACyT (Mexico); World Class University Program, National Research Foundation, NRF (Korea); CONICET and UBACyT (Argentina); Australian Research Council (Australia); FOM (The Netherlands); STFC and the Royal Society (United Kingdom); MSMT and GACR (Czech Republic); CRC Program and NSERC (Canada); Academy of Finland (Finland); BMBF and DFG (Germany); SFI (Ireland); Slovak R&D Agency (Slovakia); Programa Consolider-Ingenio 2010 (Spain); Swedish Research Council (Sweden); Swiss National Science Foundation (Switzerland); NSC (Republic of China); CAS and CNSF (China); and the A. P. Sloan Foundation (USA)

Improved Determination of the Width of the Top Quark

We present an improved determination of the total width of the top quark, Γt, using 5.4 fb-1 of integrated luminosity collected by the D0 Collaboration at the Tevatron pp- Collider. The total width Γt is extracted from the partial decay width Γ(t →Wb) and the branching fraction Β(t → Wb). Γ(t → Wb) is obtained from the t-channel single top-quark production cross section and Β(t → Wb) is measured in tt- events. For a top mass of 172.5 GeV, the resulting width is Γt = 2.00 +0:47 - 0:43 GeV. This translates to a top-quark lifetime of τt = (3.29 +0:90 -0.63) x 10-25s. We also extract an improved direct limit on the Cabibbo- Kobayashi-Maskawa quark-mixing matrix element 0.81 < │Vtb│ ≤ 1 at 95% C.L. and a limit of │Vtb ‘│< 0.59 for a high-mass fourth-generation bottom quark assuming unitarity of the fourth-generation quark-mixing matrix.We thank the staffs at Fermilab and collaborating institutions, and acknowledge support from the DOE and NSF (USA); CEA and CNRS/IN2P3 (France); FASI, Rosatom, and RFBR (Russia); CNPq, FAPERJ, FAPESP, and FUNDUNESP (Brazil); DAE and DST (India); Colciencias (Colombia); CONACyT (Mexico); NRF (Korea); CONICET and UBACyT (Argentina); FOM (The Netherlands); STFC and the Royal Society (United Kingdom); MSMT and GACR (Czech Republic); BMBF and DFG (Germany); SFI (Ireland); The Swedish Research Council (Sweden); and CAS and CNSF (China)

Combination of the Top Quark Mass Measurements from the Tevatron Collider

The top quark is the heaviest known elementary particle, with a mass about 40 times larger than the mass of its isospin partner, the bottom quark. It decays almost 100% of the time to a W boson and a bottom quark. Using top-antitop pairs at the Tevatron proton-antiproton collider, the CDF and D0 Collaborations have measured the top quark’s mass in different final states for integrated luminosities of up to 5.8 fb-1. This paper reports on a combination of these measurements that results in a more precise value of the mass than any individual decay channel can provide. It describes the treatment of the systematic uncertainties and their correlations. The mass value determined is 173.18 ± 0.56(stat) ± 0.75(syst) GeV or 173.18 ± 0.94 GeV, which has a precision of ±0.54%, making this the most precise determination of the top-quark mass.We thank the Fermilab staff and technical staffs of the participating institutions for their vital contributions and acknowledge support from the DOE and NSF (USA), ARC (Australia), CNPq, FAPERJ, FAPESP, and FUNDUNESP (Brazil), NSERC (Canada), NSC, CAS, and CNSF (China), Colciencias (Colombia), MSMT and GACR (Czech Republic), the Academy of Finland, CEA, and CNRS/IN2P3 (France), BMBF and DFG (Germany), DAE and DST (India), SFI (Ireland), INFN (Italy), MEXT (Japan), the Korean World Class University Program and NRF (Korea), CONACyT (Mexico), FOM (Netherlands), MON, NRC KI, and RFBR (Russia), the Slovak R&D Agency, the Ministerio de Ciencia e Innovacio´n, and Programa Consolider-Ingenio 2010 (Spain), The Swedish Research Council (Sweden), SNSF (Switzerland), STFC and the Royal Society (United Kingdom), and the A. P. Sloan Foundation (USA)

Measurement of the Top-Quark Mass in pp- Collisions Using Events with Two Leptons

We present a measurement of the top-quark mass (mt) in pp- collisions at √s=1.96TeV using tt- events with two leptons (ee, e μ, or μμ) and accompanying jets in 4.3 fb-1 of data collected with the D0 detector at the Fermilab Tevatron collider. We analyze the kinematically underconstrained dilepton events by integrating over their neutrino rapidity distributions. We reduce the dominant systematic uncertainties from the calibration of jet energy using a correction obtained from tt- events with a final state of a single lepton plus jets. We also correct jets in simulated events to replicate the quark flavor dependence of the jet response in data. We measure mt = 173.7 ± 2.8(stat) ±1.5(syst) GeV and combining with our analysis in 1 fb-1 of preceding data we measure mt = 174.0 ± 2.4(stat) ±1.4 (syst) GeV. Taking into account statistical and systematic correlations, a combination with the D0 matrix element result from both data sets yields mt = 173.9 ± 1.9(stat) ± 1.6(syst) GeV.We thank the staffs at Fermilab and collaborating institutions and acknowledge support from the DOE and NSF (USA); CEA and CNRS/IN2P3 (France); FASI, Rosatom and RFBR (Russia); CNPq, FAPERJ, FAPESP and FUNDUNESP (Brazil); DAE and DST (India); Colciencias (Colombia); CONACyT (Mexico); NRF (Korea); CONICET and UBACyT (Argentina); FOM (Netherlands); STFC and the Royal Society (United Kingdom); MSMT and GACR (Czech Republic); BMBF and DFG (Germany); SFI (Ireland); The Swedish Research Council (Sweden); and CAS and CNSF (China)

Search for Neutral Higgs bosons in Events with Multiple Bottom Quarks at the Tevatron

The combination of searches performed by the CDF and D0 collaborations at the Fermilab Tevatron Collider for neutral Higgs bosons produced in association with b quarks is reported. The data, corresponding to 2 : 6fb 1 of integrated luminosity at CDF and 5 : 2fb 1 at D0, have been collected in final states containing three or more b jets. Upper limits are set on the cross section multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson. Significant enhancements to the production of Higgs bosons can be found in theories beyond the standard model, for example, in supersymmetry. The results are interpreted as upper limits in the parameter space of the minimal supersymmetric standard model in a benchmark scenario favoring this decay mode.We acknowledge support from the DOE and NSF (USA), ARC (Australia), CNPq, FAPERJ, FAPESP and FUNDUNESP (Brazil), NSERC (Canada), NSC, CAS and CNSF (China), Colciencias (Colombia), MSMT and GACR (Czech Republic), the Academy of Finland, CEA and CNRS/ IN2P3 (France), BMBF and DFG (Germany), DAE and DST (India), SFI (Ireland), INFN (Italy), MEXT (Japan), the Korean World Class University Program and NRF (Korea), CONACyT (Mexico), FOM (Netherlands), MON, NRC KI and RFBR (Russia), the Slovak R&D Agency, the Ministerio de Ciencia e Innovacio ́ n, and Programa Consolider-Ingenio 2010 (Spain), The Swedish Research Council (Sweden), SNSF (Switzerland), STFC and the Royal Society (United Kingdom), and the A.P Sloan Foundation (USA

Dependence of electronic polarization on octahedral rotations in TbMnO3 from first principles

The electronic contribution to the magnetically induced polarization in orthorhombic TbMnO3 is studied from first principles. We compare the cases in which the spin cycloid, which induces the electric polarization via the spin-orbit interaction, is in either the b-c or a-b plane. We find that the electronic contribution is negligible in the first case, but much larger, and comparable to the lattice-mediated contribution, in the second case. However, we how that this behavior is an artifact of the particular pattern of octahedral rotations characterizing the structurally relaxed Pbnm crystal structure. To do so, we explore how the electronic contribution varies for a structural model of rigidly rotated MnO6 octahedra, and demonstrate that it can vary over a wide range, comparable with the lattice-mediated contribution, for both b-c and a-b spirals. We introduce a phenomenological model that is capable of describing this behavior in terms of sums of symmetry-constrained contributions arising from the displacements of oxygen atoms from the centers of the Mn-Mn bonds.Comment: 8 pages, 5 figures, 3 table

The business models of commercial urban farming in developed countries

This thesis is an analysis of the business models used in commercial urban farming in the developed world. With its global sample and praxis to include all found firms not subject to delimitations, this thesis is an extension of the academic writing that already has gone beyond the case approach in studying urban farming and alternative food networks. Moreover, it further establishes the economic perspective on alternative food networks, and introduces this perspective for commercial urban farming. Commercial urban farming can be partitioned into three main classes. - Small production, their products ranges are either very focused or very diverse. Mode of output is typically a farmer’s market and a few restaurants. - Large production, their product ranges are typically focused around leafy greens or other perishables. Mode of output is typically retail and restaurants. - Secondary purpose, their urban farming operation directly benefits another activity which provides additional revenue or lower costs for the business. The range of secondary activities includes marketing, distribution, self-harvest and recreation. These classes were found by quantifying the business models of the firms in accordance with the conceptual framework of Boons and Lüdeke-Freund (2013) in terms of binary data. The binary data matrix was then converted into a proximity matrix (Warrrens, 2008) from which an agglomerative hierarchical clustering was able to discern some useful patterns (Jain & Dubes, 1988). The classes was then analysed strategically following mainly Porter (1980). The analytical findings in this part of the thesis was mainly that the small production cluster is instable and that the firms in it are likely to either (1) expand outside the city after an initial marketing phase, (2) expand within the city and seek the business model of large production or (3) introduce or expand secondary value propositions in order to gain additional revenue or lowered costs. The exploratory results of this research are generalizable and can be used to theoretically define a sample of commercial urban farms. It can thus be used as a framework within which to apply confirmatory research. The propositions of the strategic analysis need confirmatory research to be validated. With the further analysis of commercial urban farming, this thesis contributes to a wider understanding of urban farming in general and deeper understanding of commercial urban farming in particular.Den här uppsatsen är en analys av de affärsmodeller som används vid kommersiell stadsodling i industrialiserade länder. Med ett globalt urval av firmor och en öppen urvalsmetod (n = 32) är detta en uppsats som går bortom detaljerade beskrivningar av enstaka exempel på alternativa matnätverk. Istället har intentionen varit att generalisera de övergripande mönstren samt att introducera ett affärsmässigt perspektiv på kommersiell stadsodling. Kommersiell stadsodling kan indelas i tre klasser. - Liten produktion, klassens produktutbud är antingen mycket fokuserade eller mycket breda. De vanliga försäljningskanelerna är bondemarknader och restauranger. - Stor produktion, klassens produktutbud är vanligen fokuserat runt gröna bladväxter och andra lättfördärvade grödor. Försäljningskanalerna är matbutiker och restauranger. - Sekundärt syfte, klassens stadsodlingsverksamhet gynner direkt en annan aktivitet i företaget, vars syfte är att inbringa extra omsättning eller sänka kostnader. De sekundära syftena är marknadsföring, distribution, självodling och rekreation. Dessa klasser hittades genom att affärsmodellerna för kommersiell stadsodling kvantifierades binärt i enlighet med det konceptuella ramverket som introducerades av Boons & Lüdeke-Freund (2013). Från matrisen med binär data skapades sedan en närhetsmatris (Warrens, 2008) från vilken en agglomerativ hierarkisk klassning (Jain & Dubes, 1988) lyckades finna användbara mönster. Klasserna analyserades sedan stategiskt, framför allt med Porter (1980) som rättesnöre. De analytiska fynden i den här delen av uppsatsen var att klassen liten produktion är instabil och att firmorna som ingår i den sannolikt kommer att antingen (1) expandera utanför staden efter sin inledande markndsföringsfas, (2) expandera i staden och adoptera en affärsmodell från klassen stor produktion eller (3) skapa eller vidareutveckla sekundära verksamheter för att få tillgång till extra omsättning eller kostnadsbesparningar. De undersökande resultaten i uppsatsen kan generaliseras och användas för att teoretiskt definiera ett urval av kommersiella stadsodlingsverksamheter. Det kan därmed användas som ett ramverk inom vilket bekräftande forskning kan urföras. Propositionerna som stammar från den strategiska analysen behöver bekräftade forskning för att kunna valideras. Med sin affärsmässiga analys av kommersiell stadsodling bidrar denna uppsats till en bättre förståelse av stadsodling i allmänhet och en djupare förståelse för kommersiell stadsodling i synnerhet

Repeated and Time-Correlated Morphological Convergence in Cave-Dwelling Harvestmen (Opiliones, Laniatores) from Montane Western North America

BACKGROUND: Many cave-dwelling animal species display similar morphologies (troglomorphism) that have evolved convergent within and among lineages under the similar selective pressures imposed by cave habitats. Here we study such ecomorphological evolution in cave-dwelling Sclerobuninae harvestmen (Opiliones) from the western United States, providing general insights into morphological homoplasy, rates of morphological change, and the temporal context of cave evolution. METHODOLOGY/PRINCIPAL FINDINGS: We gathered DNA sequence data from three independent gene regions, and combined these data with Bayesian hypothesis testing, morphometrics analysis, study of penis morphology, and relaxed molecular clock analyses. Using multivariate morphometric analysis, we find that phylogenetically unrelated taxa have convergently evolved troglomorphism; alternative phylogenetic hypotheses involving less morphological convergence are not supported by Bayesian hypothesis testing. In one instance, this morphology is found in specimens from a high-elevation stony debris habitat, suggesting that troglomorphism can evolve in non-cave habitats. We discovered a strong positive relationship between troglomorphy index and relative divergence time, making it possible to predict taxon age from morphology. Most of our time estimates for the origin of highly-troglomorphic cave forms predate the Pleistocene. CONCLUSIONS/SIGNIFICANCE: While several regions in the eastern and central United States are well-known hotspots for cave evolution, few modern phylogenetic studies have addressed the evolution of cave-obligate species in the western United States. Our integrative studies reveal the recurrent evolution of troglomorphism in a perhaps unexpected geographic region, at surprisingly deep time depths, and in sometimes surprising habitats. Because some newly discovered troglomorphic populations represent undescribed species, our findings stress the need for further biological exploration, integrative systematic research, and conservation efforts in western US cave habitats

Timing Aware Information Flow Security for a JavaCard-like Bytecode

AbstractCommon protection mechanisms fail to provide end-to-end security; programs with legitimate access to secret information are not prevented from leaking this to the world. Information-flow aware analyses track the flow of information through the program to prevent such leakages, but often ignore information flows through covert channels even though they pose a serious threat. A typical covert channel is to use the timing of certain events to carry information. We present a timing-aware information-flow type system for a low-level language similar to a non-trivial subset of a sequential Java bytecode. The type system is parameterized over the time model of the instructions of the language and over the algorithm enforcing low-observational equivalence, used in the prevention of implicit and timing flows