1,615 research outputs found

    Top quark production

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    We review the current status of the cross sections measurement of the top-quark at the LHC and at the Tevatron. Total production cross sections, studies using single top quark events and differential ttňČ\rm{t}\bar{\rm t} cross sections are discussed. The associated production of top quark pairs with photons, Z and W bosons, including ttňČ\rm{t}\bar{\rm t}Z and ttňČ\rm{t}\bar{\rm t}W measurements shown for the first time at LHCP2014, are presented.Comment: Proceedings of the LHCP 2014 Conferenc

    Espalhamento inelástico profundo em regime difrativo e a função de estrutura de Pomeron

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    Orientador: Roberto Jos√© Maria CovolanDisserta√ß√£o (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb WataghinResumo: √Č realizado um estudo sobre a fun√ß√£o de estrutura do Pomeron atrav√©s de dados experimentais de espalhamento inel√°stico profundo em regime difrativo, obtidos no experimento HERA ( Hadron-Electron Ring Accelerator ). Nesse estudo √© assumida a hip√≥tese da fatoriza√ß√£o , ou seja, considera-se a fun√ß√£o de estrutura difrativa como sendo dada pelo produto do fator de fluxo pela fun√ß√£o de estrutura do Pomeron. Para o fator de fluxo s√£o empregadas duas formas diferentes, sendo uma delas a usualmente obtida dentro da fenomenologia de polos de Regge, enquanto que a outra refere-se ao chamado modelo renormalizado. Mostra-se nesse trabalho que desses dois esquemas de an√°lise resultam conclus√Ķes bem diferentes quanto √† constitui√ß√£o do Pomeron em terrmosS de quarks e gluonsAbstract: A study about the Pomeron structure function based on diffractive deep inelastic scatterillg experimental data, obtailled at the HERA experiment, is performed. In this study it is assumed that the diffractive structure fullctioll factorizes, namely it is supposed to be given by the product of the flux factor and the pomeron structure functioll. For the flux factor, two different forms are employed: one that is usually obtained within the Regge pole phellomellology and the other which comes from the rellormalized approach. It is shown that these two schemes os analysis drive to very different collclusions about the pomeron collstitution in terms of quarks and gluonsMestradoF√≠sicaMestre em F√≠sic

    Differential cross section measurements for the production of a W boson in association with jets in proton‚Äďproton collisions at ‚ąös = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript ‚ąí1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an