Fusarium head blight (FHB) of wheat, caused principally by Fusarium graminearum in Canada, results in accumulation of mycotoxins in the grain. The fungus produces deoxynivalenol (DON) and its acetylated forms 3-ADON or 15-ADON. Increasing numbers of F. graminearum isolates collected in Manitoba between 1998 and 2004 were of the 3-ADON chemotype, whereas prior to 1998, the 15-ADON chemotype was considered the only significant cause of FHB in North America. Between 2008 and 2012, a series of studies were conducted at Carman (2008, 2009) and Glenlea, Manitoba (2008-2012) to monitor the ratio of 3-ADON to 15-ADON chemotypes recovered after wheat plots were artificially inoculated, usually in a 1:1 ratio of 3-ADON:15-ADON isolates of F. graminearum. Additional studies were conducted under controlled conditions. In 2008, the majority of isolates recovered from both Carman and Glenlea were of the 3-ADON chemotype. In subsequent years, however, the ratio was closer to 1:1 or sometimes with a slight predominance of 15-ADON isolates. Under controlled conditions, recovery of 15-ADON isolates predominated at lower incubation temperatures (18-22 degrees C) whereas at 28 degrees C, 3-ADON isolates were more prevalent. At moderate temperature (24 degrees C), results were mixed - seven samples had a 1:1 ratio, three had higher recovery of 3-ADON isolates, and two had higher recovery of 15-ADON. However, an examination of weather variables over the 5-year period of the field studies showed no correlation between recovery of chemotype and temperature or precipitation. ResumeLa brulure de l'epi (FHB) du ble, causee principalement au Canada par Fusarium graminearum, engendre des accumulations de mycotoxines dans les grains. Le champignon produit du deoxynivalenol (DON) et ses formes acetylees 3-ADON ou 15-ADON. De plus en plus d'isolats de F. graminearum collectes au Manitoba de 1998 a 2004 appartenaient au chimiotype du 3-ADON alors que, avant 1998, le chimiotype du 15-ADON etait considere comme la seule cause importante de FHB en Amerique du Nord. De 2008 a 2012, une serie d'etudes ont ete menees a Carman (2008, 2009) et Glenlea (2008-2012), au Manitoba, pour surveiller la proportion recuperee des chimiotypes du 3-ADON et du 15-ADON apres que les parcelles de ble avaient ete inoculees artificiellement, le rapport des isolats de F. graminearum produisant du 3-ADON et du 15-ADON etant habituellement de 1:1. Des etudes supplementaires ont ete menees dans des conditions controlees. En 2008, la majorite des isolats recuperes a Carman et a Glenlea appartenaient au chimiotype du 3-ADON. Toutefois, au cours des annees suivantes, le rapport etait plus pres de 1:1 ou parfois affichait une legere predominance des isolats produisant du 15-ADON. Dans des conditions controlees, les isolats recuperes appartenant au chimiotype du 15-ADON predominaient a des temperatures d'incubation plus basses (18 a 22 degrees C) tandis que, a 28 degrees C, les isolats appartenant au chimiotype du 3-ADON etaient plus nombreux. 24 degrees C, temperature consideree comme moderee, les resultats variaientsept echantillons affichaient un rapport de1:1, trois affichaient un rapport plus eleve de recuperation des isolats produisant du 3-ADON et deux, un rapport plus eleve d'isolats produisant du 15-ADON. Toutefois, un examen des variables meteorologiques des cinq annees qu'ont dure les etudes en champ a montre qu'il n'y avait aucune correlation entre la recuperation des chimiotypes et la temperature ou les precipitations.

The collection of a large number of B-hadron decays to hadronic final states at the CDF II Detector is possible due to the presence of a trigger that selects events based on track impact parameters. However, the nature of the selection requirements of the trigger introduces a large bias in the observed proper-decay-time distribution. A lifetime measurement must correct for this bias, and the conventional approach has been to use a Monte Carlo simulation. The leading sources of systematic uncertainty in the conventional approach are due to differences between the data and the Monte Carlo simulation. In this paper, we present an analytic method for bias correction without using simulation, thereby removing any uncertainty due to the differences between data and simulation. This method is presented in the form of a measurement of the lifetime of the B{sup -} using the mode B{sup -}{yields}D{sup 0}{pi}{sup -}. The B{sup -} lifetime is measured as {tau}{sub B}{sup -}=1.663{+-}0.023{+-}0.015 ps, where the first uncertainty is statistical and the second systematic. This new method results in a smaller systematic uncertainty in comparison to methods that use simulation to correct for the trigger bias.

The cross section for jets from b quarks produced with a W boson has been measured in pp collision data from 1.9 fb(-1) of integrated luminosity recorded by the CDF II detector at the Tevatron. The W+b-jets process poses a significant background in measurements of top quark production and prominent searches for the Higgs boson. We measure a b-jet cross section of 2.74+/-0.27(stat)+/-0.42(syst) pb in association with a single flavor of leptonic W boson decay over a limited kinematic phase space. This measured result cannot be accommodated in several available theoretical predictions.

We report a search for single top quark production with the CDF II detector using 2.1 fb-1 of integrated luminosity of pbar p collisions at sqrts=1.96 TeV. The data selected consist of events characterized by large energy imbalance in the transverse plane and hadronic jets, and no identified electrons and muons, so the sample is enriched in W -> tau nu decays. In order to suppress backgrounds, additional kinematic and topological requirements are imposed through a neural network, and at least one of the jets must be identified as a b-quark jet. We measure an excess of signal-like events in agreement with the standard model prediction, but inconsistent with a model without single top quark production by 2.1 standard deviations (sigma), with a median expected sensitivity of 1.4 sigma. Assuming a top quark mass of 175 GeV/c2 and ascribing the excess to single top quark production, the cross section is measured to be 4.9+2.5-2.2(stat+syst)pb, consistent with measurements performed in independent datasets and with the standard model prediction.

We present results of a search for anomalous production of two photons together with an electron, muon, tau lepton, missing transverse energy, or jets using p (p) over bar collision data from 1.1-2.0 fb(-1) of integrated luminosity collected by the Collider Detector at Fermilab (CDF). The event yields and kinematic distributions are examined for signs of new physics without favoring a specific model of new physics. The results are consistent with the standard model expectations. The search employs several new analysis

We report the results of a study of multi-muon events produced at the Fermilab Tevatron collider and acquired with the CDF II detector using a dedicated dimuon trigger. The production cross section and kinematics of events in which both muon candidates are produced inside the beam pipe of radius 1.5 cm are successfully modeled by known processes which include heavy flavor production. In contrast, we are presently unable to fully account for the number and properties of the remaining events, in which at least one muon candidate is produced outside of the beam pipe, in terms of the same understanding of the CDF II detector, trigger, and event reconstruction.

We present a search for supersymmetric neutrino ˜ν production using the Tevatron p¯p collision data collected with the CDF II detector and corresponding to an integrated luminosity of 1 fb−1. We focus on the scenarios predicted by the R-parity violating (RPV) supersymmetric models in which sneutrinos decay to two charged leptons of different flavor. With the data consistent with the standard model expectations, we set upper limits on σ(p¯p→˜ν)×BR(˜ν→eμ,μτ,eτ) and use these results to constrain the RPV couplings as a function of the sneutrino mass.Received 10 May 2010DOI:https://doi.org/10.1103/PhysRevLett.105.191801© 2010 The American Physical Society

We present three measurements of the top-quark mass in the lepton plus jets channel with approximately 1.9 fb-1 of integrated luminosity collected with the CDF II detector using quantities with minimal dependence on the jet energy scale. One measurement exploits the transverse decay length of b-tagged jets to determine a top-quark mass of 166.9+9.5-8.5 (stat) +/- 2.9 (syst) GeV/c2, and another the transverse momentum of electrons and muons from W-boson decays to determine a top-quark mass of 173.5+8.8-8.9 (stat) +/- 3.8 (syst) GeV/c2. These quantities are combined in a third, simultaneous mass measurement to determine a top-quark mass of 170.7 +/- 6.3 (stat) +/- 2.6 (syst) GeV/c2.

We report a measurement of the ratio of the tt to Z/γ{*} production cross sections in sqrt[s]=1.96 TeV pp collisions using data corresponding to an integrated luminosity of up to 4.6 fb{-1}, collected by the CDF II detector. The tt cross section ratio is measured using two complementary methods, a b-jet tagging measurement and a topological approach. By multiplying the ratios by the well-known theoretical Z/γ{*}→ll cross section predicted by the standard model, the extracted tt cross sections are effectively insensitive to the uncertainty on luminosity. A best linear unbiased estimate is used to combine both measurements with the result σ{tt}=7.70±0.52 pb, for a top-quark mass of 172.5 GeV/c{2}.

We report measurements of the polarization of W bosons from top-quark decays using 2.7 fb{-1} of pp collisions collected by the CDF II detector. Assuming a top-quark mass of 175  GeV/c{2}, three measurements are performed. A simultaneous measurement of the fraction of longitudinal (f{0}) and right-handed (f{+}) W bosons yields the model-independent results f{0}=0.88±0.11(stat)±0.06(syst) and f{+}=-0.15±0.07(stat)±0.06(syst) with a correlation coefficient of -0.59. A measurement of f{0} [f{+}] constraining f{+} [f{0}] to its standard model value of 0.0 [0.7] yields f{0}=0.70±0.07(stat)±0.04(syst) [f{+}=-0.01±0.02(stat)±0.05(syst)]. All these results are consistent with standard model expectations. We achieve the single most precise measurements of f{0} for both the model-independent and model-dependent determinations.

We report on a search for the standard model Higgs boson produced in association with a W or Z boson in pp collisions at square root(s)=1.96 TeV recorded by the CDF II experiment at the Tevatron in a data sample corresponding to an integrated luminosity of 2.1 fb(-1). We consider events which have no identified charged leptons, an imbalance in transverse momentum, and two or three jets where at least one jet is consistent with originating from the decay of a b hadron. We find good agreement between data and background predictions. We place 95% confidence level upper limits on the production cross section for several Higgs boson masses ranging from 110 GeV/c(2) to 150 GeV/c(2). For a mass of 115 GeV/c(2) the observed (expected) limit is 6.9 (5.6) times the standard model prediction.

We present a search for standard model (SM) Higgs boson production using pp collision data at square root(s) = 1.96 TeV, collected with the CDF II detector and corresponding to an integrated luminosity of 4.8 fb(-1). We search for Higgs bosons produced in all processes with a significant production rate and decaying to two W bosons. We find no evidence for SM Higgs boson production and place upper limits at the 95% confidence level on the SM production cross section (sigma(H)) for values of the Higgs boson mass (sigma(H)) in the range from 110 to 200 GeV. These limits are the most stringent for m(H) > 130 GeV and are 1.29 above the predicted value of sigma(H) for c = 165 GeV.