997 resultados para 1[Habermas]


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We report on a search for the standard model Higgs boson produced in association with a $W$ or $Z$ boson in $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ 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 predictions. We place 95% confidence level upper limits on the production cross section for several Higgs boson masses ranging from 110$\gevm$ to 150$\gevm$. For a mass of 115$\gevm$ the observed (expected) limit is 6.9 (5.6) times the standard model prediction.

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Most of the world’s languages lack electronic word form dictionaries. The linguists who gather such dictionaries could be helped with an efficient morphology workbench that adapts to different environments and uses. A widely usable workbench could be characterized, ideally, as generally applicable, extensible, and freely available (GEA). It seems that such a solution could be implemented in the framework of finite-state methods. The current work defines the GEA desiderata and starts a series of articles concerning these desiderata in finite- state morphology. Subsequent parts will review the state of the art and present an action plan toward creating a widely usable finite-state morphology workbench.

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We present a search for the lightest supersymmetric partner of the top quark in proton-antiproton collisions at a center-of-mass energy √s=1.96  TeV. This search was conducted within the framework of the R parity conserving minimal supersymmetric extension of the standard model, assuming the stop decays dominantly to a lepton, a sneutrino, and a bottom quark. We searched for events with two oppositely-charged leptons, at least one jet, and missing transverse energy in a data sample corresponding to an integrated luminosity of 1  fb-1 collected by the Collider Detector at Fermilab experiment. No significant evidence of a stop quark signal was found. Exclusion limits at 95% confidence level in the stop quark versus sneutrino mass plane are set. Stop quark masses up to 180  GeV/c2 are excluded for sneutrino masses around 45  GeV/c2, and sneutrino masses up to 116  GeV/c2 are excluded for stop quark masses around 150  GeV/c2.

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We report the first measurement of the cross section for Z boson pair production at a hadron collider. This result is based on a data sample corresponding to 1.9 fb-1 of integrated luminosity from ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. In the llll channel, we observe three ZZ candidates with an expected background of 0.096^{+0.092}_{-0.063} events. In the llnunu channel, we use a leading-order calculation of the relative ZZ and WW event probabilities to discriminate between signal and background. In the combination of llll and llnunu channels, we observe an excess of events with a probability of $5.1\times 10^{-6}$ to be due to the expected background. This corresponds to a significance of 4.4 standard deviations. The measured cross section is sigma(ppbar -> ZZ) = 1.4^{+0.7}_{-0.6} (stat.+syst.) pb, consistent with the standard model expectation.

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In the title molecule, C23H14N4, the triazoloisoquinoline ring system is nearly planar, with an r.m.s. deviation of 0.038 (2) angstrom and a maximum deviation of -0.030 (2) angstrom from the mean plane of the triazole ring C atom which is bonded to the benzene ring. The benzene and phenyl rings are twisted by 57.65 (8) and 53.60 (9)degrees, respectively, with respect to the mean plane of the triazoloisoquinoline ring system. In the crystal structure, molecules are linked by weak aromatic pi-pi interactions [centroid-centroid distance = 3.8074 (12) angstrom]. In addition, the crystal structure exhibits a nonclassical intermolecular C-H center dot center dot center dot N hydrogen bond.

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In the title molecule, C22H14ClN3, the triazoloisoquinoline ring system is approximately planar, with an r.m.s. deviation of 0.033 (2) angstrom and a maximum departure from the mean plane of 0.062 (1) angstrom for the triazole ring C atom, bonded to the benzene ring. The benzene and phenyl rings are twisted by 57.02 (6) and 62.16 (6)degrees, respectively, to the mean plane of the triazoloisoquinoline ring system. The molecule is stabilized by a weak intramolecular pi-pi interaction [centroid-centroid distance = 3.7089 (10) angstrom] between the benzene and phenyl rings. In the crystal structure, weak intermolecular C-H center dot center dot center dot N hydrogen bonds and C-H center dot center dot center dot pi interactions link the molecules.

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The conformation about the ethene bond [1.316 (3) angstrom] in the title compound, C25H18BrNO, is E. The quinoline ring forms dihedral angles of 67.21 (10) and 71.68 (10)degrees with the benzene and bromo-substituted benzene rings, respectively. High-lighting the non-planar arrangement of aromatic rings, the dihedral angle formed between the benzene rings is 58.57 (12)degrees.

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In the title compound, C18H11ClN2O2, the isatin and 2-chloro-3-methylquinoline units are both almost planar, with r.m.s.deviations of 0.0075 and 0.0086 angstrom, respectively, and the dihedral angle between the mean planes of the two units is 83.13 (7)degrees. In the crystal, a weak intermolecular C-H center dot center dot center dot O interaction links the molecules into chains along the c axis.

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With a view to understanding the mechanism of the formation of 6-methoxy-2,2-(tetrachloro--phenylenedioxy)-naphthalen-1 (2H)-one (IIIa) in the reaction of 6-methoxy-1-tetralone (Ia) with tetrachloro-1,2-benzoquinone (II), the reaction of (II) with various tetralones and naphthols has been studied. Reaction with either α-tetralone or α-naphthol gives 2,2-(tetrachloro-o-phenylenedioxy)naphthalen-1 (2H)-one (IIIb), whereas reaction with either β-tetralone or β-naphthol gives a mixture of (IIIb) and ,1-(tetrachloro-o-phenylenedioxy)-naphthalen-2 (1H)-one (IX), with the former predominating. Further, reactions of (II) with 7-methoxy-3,4-dihydrophenanthren- 1 (2H)-one and m-methoxyphenol gave respectively 7-methoxy- ,2-(tetrachloro-o- phenylenedioxy)phenanthren-1 (2H)-one (VII) and 3-methoxy-6,6-(tetrachloro-o- phenylenedioxy)cyclohexa-2,4-dien-1-one (VIII). Structures of all these compounds have been proved on the basis of i.r. and n.m.r. data. The pathway to the formation of the condensates (III) is discussed.

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dl-3-Methoxy-11-oxo-17β-carboxy-1,3,5(10),6,8-estrapentaene has been converted to dl-3-methoxy-17β-carboxy-1,3,5(10)-estratriene in fairly good yield.

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3-Methyl-4-carboxy-2-(2′-methoxy-6′-naphthyl)cyclopenten-3-acetic acid, prepared from trans methyl 2-methyl-3-carbomethoxycyclopentanon-2-acetate and 2-methoxy-6-lithionaphthalene, on ring closure and catalytic hydrogenation gave dl-3-methoxy-17β-carboxy-1,3,5(10),6,8-estrapentaene.

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Copper(II) complexes of 1-benzyl-2-phenylbenzimidazole (BPBI) of the general formula Cu(BPBI)2X2, nH2O [X= Cl-, Br-, NO3 or OAc- (n = O) and X = NO3- or 1 2SO42-(n = 2H2O)] have been prepared. The complexes are found to be nonelectrolytes in nitrobenzene. Conductivity in nonaqueous media, magnetic susceptibilities and i.r. and electronic spectra of the complexes are reported. A tetragonally distorted octahedral structure has been suggested for these complexes.

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We present the first direct measurement of the $W$ production charge asymmetry as a function of the $W$ boson rapidity $\yW$ in $\ppbar$ collisions at $\sqrt{s} = 1.96$ $\TeV$. We use a sample of $\wenu$ events in data from 1 $\ifb$ of integrated luminosity collected using the CDF II detector. In the region $|\yW|

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A search for a narrow diphoton mass resonance is presented based on data from 3.0 fb^{-1} of integrated luminosity from p-bar p collisions at sqrt{s} = 1.96 TeV collected by the CDF experiment. No evidence of a resonance in the diphoton mass spectrum is observed, and upper limits are set on the cross section times branching fraction of the resonant state as a function of Higgs boson mass. The resulting limits exclude Higgs bosons with masses below 106 GeV at a 95% Bayesian credibility level (C.L.) for one fermiophobic benchmark model.