2,016 research outputs found

    Estimativa dos coeficientes de cultivo (kc) de videiras para suco.

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    A fração da área coberta pelo dossel (fc) tem sido empregada, em diferentes regiões, para a estimativa do coeficiente de cultivo (Kc) de videiras. O presente trabalho teve por objetivo estimar os valores de Kc de videiras destinadas à produção de uvas para elaboração de suco com base nos valores de fc, nas condições do noroeste paulista. As avaliações foram realizadas de agosto a novembro de 2016 no município de Votuporanga (SP), com as cultivares Isabel Precoce e BRS Carmem enxertadas sobre os porta-enxertos ?IAC 572? e ?IAC 766?. As videiras foram conduzidas no sistema espaldeira e irrigadas por microaspersores. Os valores de fc foram obtidos ao longo do ciclo da cultura e correlacionados à soma térmica diária (ST) por meio de modelos de regressão. Os coeficientes de cultivo (Kc), foram obtidos em função da fc com base no modelo de Allen e Pereira (2009). Para a cultivar BRS Carmem, os valores de fc em função de ST cresceram de forma contínua, segundo um modelo quadrático, enquanto que, para a cultivar Isabel Precoce, os dados se ajustaram melhor ao modelo de Mitscherlich, apresentando um rápido crescimento inicial e se estabilizando após 500 °C dia, aproximadamente. Os valores médios estimados de Kc para as cultivares Isabel Precoce e BRS Carmem foram iguais a 0,81 e 0,74, respectivamente. O modelo empregado nas avaliações permite a realização de estimativas dos valores de Kc para diferentes condições de cultivo

    Long-lived neutral-kaon flux measurement for the KOTO experiment

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    The KOTO (K0K^0 at Tokai) experiment aims to observe the CP-violating rare decay KLπ0ννˉK_L \rightarrow \pi^0 \nu \bar{\nu} by using a long-lived neutral-kaon beam produced by the 30 GeV proton beam at the Japan Proton Accelerator Research Complex. The KLK_L flux is an essential parameter for the measurement of the branching fraction. Three KLK_L neutral decay modes, KL3π0K_L \rightarrow 3\pi^0, KL2π0K_L \rightarrow 2\pi^0, and KL2γK_L \rightarrow 2\gamma were used to measure the KLK_L flux in the beam line in the 2013 KOTO engineering run. A Monte Carlo simulation was used to estimate the detector acceptance for these decays. Agreement was found between the simulation model and the experimental data, and the remaining systematic uncertainty was estimated at the 1.4\% level. The KLK_L flux was measured as (4.183±0.017stat.±0.059sys.)×107(4.183 \pm 0.017_{\mathrm{stat.}} \pm 0.059_{\mathrm{sys.}}) \times 10^7 KLK_L per 2×10142\times 10^{14} protons on a 66-mm-long Au target.Comment: 27 pages, 16 figures. To be appeared in Progress of Theoretical and Experimental Physic

    Desenvolvimento vegetativo e tensão da água no solo em videiras para suco sobre dois porta-enxertos.

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    RESUMO: O presente trabalho teve por objetivo avaliar o efeito de dois porta-enxertos sobre o desenvolvimento vegetativo e as tensões da água no solo em videiras destinadas à elaboração de suco, sob condições irrigadas. As avaliações foram realizadas de agosto a dezembro de 2015 no município de Votuporanga (SP), com a cultivar Isabel Precoce enxertada sobre os portaenxertos ?IAC 572? e ?IAC 766?. As plantas foram sustentadas no sistema espaldeira e irrigadas por microaspersores. Tensiômetros foram instalados a 0,10 m e 0,30 m de profundidade, para monitorar as tensões da água no solo. Foram determinados os índices de área foliar, a altura da copa e a porcentagem da área sombreada das videiras. As tensões da água no solo apresentaram comportamento semelhante nos dois porta-enxertos. Não foram observadas diferenças significativas entre as variáveis de crescimento vegetativo nas videiras. Concluiu-se que os porta-enxertos ?IAC 572? e ?IAC 766? não afetaram o desenvolvimento vegetativo e as tensões da água no solo para a cultivar Isabel Precoce, em condições irrigadas. PALAVRAS-CHAVE: viticultura, irrigação, evapotranspiraçã

    Study of CP violation in Dalitz-plot analyses of B0 --> K+K-KS, B+ --> K+K-K+, and B+ --> KSKSK+

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    We perform amplitude analyses of the decays B0K+KKS0B^0 \to K^+K^-K^0_S, B+K+KK+B^+ \rightarrow K^+K^-K^+, and B+KS0KS0K+B^+ \to K^0_S K^0_S K^+, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470×106470\times 10^6 BBˉB\bar{B} decays, collected with the BABAR detector at the PEP-II asymmetric-energy BB factory at the SLAC National Accelerator Laboratory. For B+K+KK+B^+ \to K^+K^-K^+, we find a direct CP asymmetry in B+ϕ(1020)K+B^+ \to \phi(1020)K^+ of ACP=(12.8±4.4±1.3)A_{CP}= (12.8\pm 4.4 \pm 1.3)%, which differs from zero by 2.8σ2.8 \sigma. For B0K+KKS0B^0 \to K^+K^-K^0_S, we measure the CP-violating phase βeff(ϕ(1020)KS0)=(21±6±2)\beta_{\rm eff} (\phi(1020)K^0_S) = (21\pm 6 \pm 2)^\circ. For B+KS0KS0K+B^+ \to K^0_S K^0_S K^+, we measure an overall direct CP asymmetry of ACP=(45+4±2)A_{CP} = (4 ^{+4}_{-5} \pm 2)%. We also perform an angular-moment analysis of the three channels, and determine that the fX(1500)f_X(1500) state can be described well by the sum of the resonances f0(1500)f_0(1500), f2(1525)f_2^{\prime}(1525), and f0(1710)f_0(1710).Comment: 35 pages, 68 postscript figures. v3 - minor modifications to agree with published versio

    Observation of Hadronic W Decays in t-tbar Events with the Collider Detector at Fermilab

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    We observe hadronic W decays in t-tbar -> W (-> l nu) + >= 4 jet events using a 109 pb-1 data sample of p-pbar collisions at sqrt{s} = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). A peak in the dijet invariant mass distribution is obtained that is consistent with W decay and inconsistent with the background prediction by 3.3 standard deviations. From this peak we measure the W mass to be 77.2 +- 4.6 (stat+syst) GeV/c^2. This result demonstrates the presence of two W bosons in t-tbar candidates in the W (-> l nu) + >= 4 jet channel.Comment: 20 pages, 4 figures, submitted to PR

    Search for Chargino-Neutralino Associated Production at the Fermilab Tevatron Collider

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    We have searched in ppˉp \bar{p} collisions at s\sqrt{s} = 1.8 TeV for events with three charged leptons and missing transverse energy. In the Minimal Supersymmetric Standard Model, we expect trilepton events from chargino-neutralino (\chione \chitwo) pair production, with subsequent decay into leptons. We observe no candidate e+ee±e^+e^-e^\pm, e+eμ±e^+e^-\mu^\pm, e±μ+μe^\pm\mu^+\mu^- or μ+μμ±\mu^+\mu^-\mu^\pm events in 106 pb1^{-1} integrated luminosity. We present limits on the sum of the branching ratios times cross section for the four channels: \sigma_{\chione\chitwo}\cdot BR(\chione\chitwo\to 3\ell+X) 81.5 \mgev\sp and M_\chitwo > 82.2 \mgev\sp for tanβ=2\tan\beta=2, μ=600\mu =-600~\mgev\sp and M_\squark= M_\gluino.Comment: 9 pages and 3 figure

    Measurement of WγW\gamma and ZγZ\gamma Production in ppˉp\bar{p} Collisions at s\sqrt{s} = 1.96 TeV

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    The Standard Model predictions for WγW\gamma and ZγZ\gamma production are tested using an integrated luminosity of 200 pb1^{-1} of \ppbar collision data collected at the Collider Detector at Fermilab. The cross sections are measured selecting leptonic decays of the WW and ZZ bosons, and photons with transverse energy ET>7E_T>7 GeV that are well separated from leptons. The production cross sections and kinematic distributions for the WγW\gamma and ZγZ\gamma are compared to SM predictions.Comment: 7 pages, 4 figures, submitted to PR

    Inclusive Search for Anomalous Production of High-pT Like-Sign Lepton Pairs in Proton-Antiproton Collisions at sqrt{s}=1.8 TeV

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    We report on a search for anomalous production of events with at least two charged, isolated, like-sign leptons with pT > 11 GeV/c using a 107 pb^-1 sample of 1.8 TeV ppbar collisions collected by the CDF detector. We define a signal region containing low background from Standard Model processes. To avoid bias, we fix the final cuts before examining the event yield in the signal region using control regions to test the Monte Carlo predictions. We observe no events in the signal region, consistent with an expectation of 0.63^(+0.84)_(-0.07) events. We present 95% confidence level limits on new physics processes in both a signature-based context as well as within a representative minimal supergravity (tanbeta = 3) model.Comment: 15 pages, 4 figures. Minor textual changes, cosmetic improvements to figures and updated and expanded reference

    Search for Narrow Diphoton Resonances and for gamma-gamma+W/Z Signatures in p\bar p Collisions at sqrt(s)=1.8 TeV

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    We present results of searches for diphoton resonances produced both inclusively and also in association with a vector boson (W or Z) using 100 pb^{-1} of p\bar p collisions using the CDF detector. We set upper limits on the product of cross section times branching ratio for both p\bar p\to\gamma\gamma + X and p\bar p\to\gamma\gamma + W/Z. Comparing the inclusive production to the expectations from heavy sgoldstinos we derive limits on the supersymmetry-breaking scale sqrt{F} in the TeV range, depending on the sgoldstino mass and the choice of other parameters. Also, using a NLO prediction for the associated production of a Higgs boson with a W or Z boson, we set an upper limit on the branching ratio for H\to\gamma\gamma. Finally, we set a lower limit on the mass of a `bosophilic' Higgs boson (e.g. one which couples only to \gamma, W, and Z$ bosons with standard model couplings) of 82 GeV/c^2 at 95% confidence level.Comment: 30 pages, 11 figure

    Measurement of the Lifetime Difference Between B_s Mass Eigenstates

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    We present measurements of the lifetimes and polarization amplitudes for B_s --> J/psi phi and B_d --> J/psi K*0 decays. Lifetimes of the heavy (H) and light (L) mass eigenstates in the B_s system are separately measured for the first time by determining the relative contributions of amplitudes with definite CP as a function of the decay time. Using 203 +/- 15 B_s decays, we obtain tau_L = (1.05 +{0.16}/-{0.13} +/- 0.02) ps and tau_H = (2.07 +{0.58}/-{0.46} +/- 0.03) ps. Expressed in terms of the difference DeltaGamma_s and average Gamma_s, of the decay rates of the two eigenstates, the results are DeltaGamma_s/Gamma_s = (65 +{25}/-{33} +/- 1)%, and DeltaGamma_s = (0.47 +{0.19}/-{0.24} +/- 0.01) inverse ps.Comment: 8 pages, 3 figures, 2 tables; as published in Physical Review Letters on 16 March 2005; revisions are for length and typesetting only, no changes in results or conclusion
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