4,366 research outputs found

    A New Method Of Distinguishing Models For The High-Q2Q^2 Events At HERA

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    Many explanations for the excess high-Q^2 e+p→e+Xe^+p \to e^+X events from H1 and ZEUS at HERA have been proposed each with criticisms. We propose a new method to distinguish different models by looking at a new distribution which is insensitive to parton distribution function but sensitive to new physics.Comment: 11 pages in revtex plus 3 figures in postscrip

    CP violation in Higgs decays

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    We study CP violation in fermion pair decays of Higgs boson. We idenfy some CP odd observables related to the tree level decay amplitude. We find that a few thousand Higgs boson decay events can already provide important information about CP violation. If the Higgs boson is produced, such an analysis could be carried out at the SSC, LHC and NLC.Comment: 9 pages, Revtex, UM-P-93/11, OZ-93/

    Requirement for the induced expression of a cell wall associated receptor kinase for survival during the pathogen response

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    Pathogen infection of angiosperms must rely on some interaction between the extracellular matrix (ECM) and the invading agent, and may be accompanied by signaling between the ECM and cytoplasm. An Arabidopsis cell wall associated receptor kinase (Wak1) has an amino-terminal domain that is tightly associated with the ECM, spans the plasma membrane and has a cytoplasmic protein kinase domain. Wak1 expression is induced when Arabidopsis plants are infected with pathogen, or when the pathogen response is stimulated either by exogenous salicylate (SA) or its analog 2,2-dichloroisonicotinic acid (INA). This Wak1 induction requires the positive regulator NPR1/NIM1. Thus Wak1 is a pathogen-related (PR) protein. Expression of an antisense and a dominant negative allele of Wak1 shows that induced expression of Wak1 is needed for a plant to survive if stimulated by INA. Ectopic expression of the entire Wak1, or the kinase domain alone, can provide resistance to otherwise lethal SA levels. These experiments suggest that Wak1 expression and other PR proteins are protecting plants from detrimental effects incurred during the pathogen response. These results provide a direct link between a protein kinase that could mediate signals from the ECM, to the events that are precipitated by a pathogen infection

    CP violation in J/ψ→ΛΛˉJ/\psi \rightarrow \Lambda \bar \Lambda

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    We study CP violation in J/ψ→ΛΛˉJ/\psi \rightarrow \Lambda \bar{\Lambda} decay. This decay provides a good place to look for CP violation. Some observables are very sensitive to the Λ\Lambda electric dipole moment dΛd_\Lambda and therefore can be used to improve the experimental upper bound on dΛd_\Lambda. CP violations in the lepton pair decays of J/ψJ/\psi and Υ\Upsilon are also discussed.Comment: 8 pages, RevTex, UM-P-92/113, OZ-92/3

    A Computational Approach for the Rational Design of Bimetallic Clusters for Ethanol Formation from Syn-gas

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    A major challenge associated with the synthesis of ethanol from syn-gas is an inability to find a low-cost catalyst that promotes the proper combination of CO dissociation and CO insertion steps, so as to yield ethanol as the primary reaction product and inhibit the formation of methane, methanol, longer chain alkanes, and other coking reaction products. We used quantum mechanical simulations for the rational design of bimetallic catalysts. Several promising 13-atom bimetallic clusters were selected by the identification of key reaction descriptors for ethanol formation reaction. Density Functional Theory (DFT) simulations and Bronsted-Evans-Polanyi (BEP) relations were used to map out the full reaction mechanism from syn-gas to ethanol. Selectivity analysis was conducted including hydrocarbons, methanol, acetaldehyde and ethanol as products. Microkinetic models were built, considering all necessary adsorption and reaction steps as well as the diffusion of intermediate species between different metal surface sites. More general selectivity trends were identified by altering the surface concentrations of various metal sites. These simulations indicate the nature and stability of the various bimetallic nanocatalysts and more importantly identify specific metal combinations that are ideally suited for ethanol production
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