9 research outputs found

    Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV

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    Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7  fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale

    Searches for electroweak neutralino and chargino production in channels with Higgs, Z, and W bosons in pp collisions at 8 TeV

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    Searches for supersymmetry (SUSY) are presented based on the electroweak pair production of neutralinos and charginos, leading to decay channels with Higgs, Z, and W bosons and undetected lightest SUSY particles (LSPs). The data sample corresponds to an integrated luminosity of about 19.5 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV collected in 2012 with the CMS detector at the LHC. The main emphasis is neutralino pair production in which each neutralino decays either to a Higgs boson (h) and an LSP or to a Z boson and an LSP, leading to hh, hZ, and ZZ states with missing transverse energy (E-T(miss)). A second aspect is chargino-neutralino pair production, leading to hW states with E-T(miss). The decays of a Higgs boson to a bottom-quark pair, to a photon pair, and to final states with leptons are considered in conjunction with hadronic and leptonic decay modes of the Z and W bosons. No evidence is found for supersymmetric particles, and 95% confidence level upper limits are evaluated for the respective pair production cross sections and for neutralino and chargino mass values

    Yield, chemical composition and chlorophyll relative content of Tanzania and Mombaça grasses irrigated and fertilized with nitrogen after corn intercropping

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    Avaliou-se o efeito da ausĂȘncia e da aplicação de trĂȘs doses de nitrogĂȘnio (50, 100 e 200 kg ha-1 de N) e quatro Ă©pocas de corte no inverno/primavera (julho a outubro) sobre a produtividade de massa seca (PMS), os teores relativos de clorofila (ICF _ Ă­ndice de clorofila foliar) e os teores de nutrientes digestĂ­veis totais (NDT), proteĂ­na bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ĂĄcido (FDA) e lignina, bem como suas respectivas correlaçÔes nos capins tanzĂąnia e mombaça apĂłs o consĂłrcio com milho em um Latossolo Vermelho distrofĂ©rrico. O delineamento experimental utilizado foi o de blocos casualizados, em parcelas subdivididas, com quatro repetiçÔes. As maiores PMS ocorreram com o aumento do fotoperĂ­odo (a partir de agosto), no entanto, as respostas Ă  adubação nitrogenada ao longo dos cortes diferiram entre e dentre os capins. em sistema de integração lavoura-pecuĂĄria irrigado sob condiçÔes de cerrado, Ă© tecnicamente viĂĄvel o estabelecimento dos capins tanzĂąnia e mombaça em consĂłrcio com o milho no momento da semeadura ou por ocasiĂŁo da adubação nitrogenada de cobertura, visto que, mesmo na ausĂȘncia de adubação nitrogenada, foi produzida quantidade satisfatĂłria de forragem, com PMS mĂ©dia de 2.000 kg ha-1 por corte na Ă©poca de maior escassez de volumoso para os animais (inverno/primavera). A adubação nitrogenada apĂłs a colheita do milho eleva a PMS e melhora a composição bromatolĂłgica dos capins, com aumento dos teores relativos de clorofila e PB no inverno/primavera, alĂ©m de aumento dos teores de NDT e redução dos teores de FDN e FDA atĂ© o mĂȘs de setembro. O Ă­ndice de clorofila foliar pode ser utilizado para estimar a PMS e o teor de PB, bem como indicar a necessidade de adubação nitrogenada dos capins tanzĂąnia e mombaça submetidos a corte.It was evaluated the effect of the absence and of application of three nitrogen doses (50, 100 and 200 kg ha-1of N) and four harvest times in the winter/spring season (from July to October) on dry mass yield (DMY), on the relative chlorophyll contents (ICF _ leaf chlorophyll index) and on the contents of total digestible nutrients (TDN), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin, and their respective correlations on Tanzania and Mombaça grasses after intercrop with corn in distroferric red latosol (Oxisol) soil as well. It was used a random block design, in split-plot with four replicates. The greatest DMY occured with the increase of photoperiod (from August), neverthless responses to nitrogen fertilization over cuts difered among the grasses. In an irrigated crop-livestock integration system under cerrado conditions, it is technically feasible the establishment of Tanzania and Mombaça grass intercroped with corn at sowing or if cover nitrogen fertilization is performed because even in the abscence of nitrogen fertilization, great satisfactory quantity of forage was produced, with average DMY of 2,000 kg ha-1 per cut during the highest shortage of roughage for animals (winter/spring). Nitrogen fertilization after corn harvest increases DMY and improves bromatologic composition of the grasses, as contents of chlorophyll and CP in winter/spring is increased, besides the increase of contents of TDN and a reduction on the contents of NDF and ADF until September. Leaf chlorophyll index can be used to estimate the DMY and CP content and as a marker of the need of nitrogen fertilization of Tanzania and Mombaça grasses submitted to cutting

    Measurement of the t \bart production cross section in the dilepton channel in pp collisions at \sqrts = 8 TeV

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    Search for Standard Model Production of Four Top Quarks in the Lepton + Jets Channel in pp Collisions at \sqrts = 8 TeV

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    Measurement of jet multiplicity distributions in \mathrm t\overline\mathrm t production in pp collisions at \sqrts = 7\,\text TeV

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    Search for the associated production of the Higgs boson with a top-quark pair

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