5,959 research outputs found

    Search for a SM Higgs boson in the diphoton plus EMISS T channel

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    In this paper I discuss the search for a Standard Model (SM) Higgs boson in the diphoton plus missing transverse energy (missing ET or EMISS T ) channel using 20.7 fb‚ąí1 of data recorded by the ATLAS detector in the year 2012. Higgs boson at LHC can be generated through different processes: gluon-gluon fusion (‚ąľ 85%), vector boson fusion (‚ąľ 10%), W/Z associated production (‚ąľ 5%) and top-antitop fusion (< 1%). The applied selection is optimized to isolate events from Higgs boson production associated with a W or Z boson requiring the presence of EMISS T from Z/W decay into neutrinos in addition to two isolated energetic photons. The sensitivity of this analysis is presented and found to be at a level above 5 times the predicted Standard Model cross-section

    Genuine Non-Self-Averaging and Ultra-Slow Convergence in Gelation

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    In irreversible aggregation processes droplets or polymers of microscopic size successively coalesce until a large cluster of macroscopic scale forms. This gelation transition is widely believed to be self-averaging, meaning that the order parameter (the relative size of the largest connected cluster) attains well-defined values upon ensemble averaging with no sample-to-sample fluctuations in the thermodynamic limit. Here, we report on anomalous gelation transition types. Depending on the growth rate of the largest clusters, the gelation transition can show very diverse patterns as a function of the control parameter, which includes multiple stochastic discontinuous transitions, genuine non-self-averaging and ultra-slow convergence of the transition point. Our framework may be helpful in understanding and controlling gelation.Comment: 8 pages, 10 figure

    Kinks and waterfalls as signatures of competing order in angle-resolved photoemission spectra of La_{2-x}Sr_xCuO_4

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    We show that the so-called kinks and waterfalls observed in angle-resolved photoemission spectra of La2-xSrxCuO4, a prototypical high-Tc superconducting cuprate, result from the coupling of quasiparticles with two distinct nearly critical collective modes with finite characteristic wave vectors, typical of charge and spin fluctuations near a stripe instability. Both phonon-like charge and spin collective modes are needed to account for the kinked quasiparticle dispersions. This clarifies the long-standing question whether kinks are due to phonons or spin waves and the nature of the bosonic mediators of the electron-electron effective interaction in La2-xSrxCuO4.Comment: 5 pages, 4 figure

    Fenologia reprodutiva de Maytenus ilicifolia (Celastraceae) na Floresta Nacional de Irati, Paran√°, Brasil.

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    (Reproductive phenology of Maytenus ilicifolia (Celastraceae) in the Irati National Forest, Paran√°, Brazil). The present study investigates the reproductive phenology of a natural population of Maytenus ilicifolia Mart. ex Reissek from the Mixed Ombrophylous Forest (Araucaria Forest). The phenological study was carried out from April 2003 to March 2005, on 78 adult trees. The intensity of phenological events was estimated based on the scale of Fournier. The population showed seasonal behavior. A significant correlation was observed between temperature, day length and flowering. Two floral types were identified, one pistillate and the other staminate, and together with the phenology patterns results a dioecious characteristic for the species is suggested
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