832 resultados para Brett Horton
Resumo:
The CMS detector is designed around a large 4 T superconducting solenoid, enclosed in a 12 000-tonne steel return yoke. A detailed map of the magnetic field is required for the accurate simulation and reconstruction of physics events in the CMS detector, not only in the inner tracking region inside the solenoid but also in the large and complex structure of the steel yoke, which is instrumented with muon chambers. Using a large sample of cosmic muon events collected by CMS in 2008, the field in the steel of the barrel yoke has been determined with a precision of 3 to 8% depending on the location. © 2010 IOP Publishing Ltd and SISSA.
Resumo:
The performance of muon reconstruction in CMS is evaluated using a large data sample of cosmic-ray muons recorded in 2008. Efficiencies of various high-level trigger, identification, and reconstruction algorithms have been measured for a broad range of muon momenta, and were found to be in good agreement with expectations from Monte Carlo simulation. The relative momentum resolution for muons crossing the barrel part of the detector is better than 1% at 10 GeV/c and is about 8% at 500 GeV/c, the latter being only a factor of two worse than expected with ideal alignment conditions. Muon charge misassignment ranges from less than 0.01% at 10GeV/c to about 1% at 500 GeV/c. © 2010 IOP Publishing Ltd and SISSA.
Influência da aplicação de vinhaça na capacidade de Infiltração de um solo de textura franco arenosa
Resumo:
The objective of this study was to analyze effects in different depth in soil water infiltration and to verify the Horton and Kostiakov-Lewis models adequacy in infiltration rate estimate. The treatments were five doses of vinasse (0, 200, 250, 300 and 350 m3?ha1?. The vinasse application reduced the soil erosion risk increasing the possibility of runoff. The Horton model had the best adjustment on the observed data, and the Kostiakov-Lewis model overestimated the infiltration rate values.
Resumo:
A search motivated by supersymmetric models with light top squarks is presented using proton-proton collision data recorded with the CMS detector at a center-of-mass energy of √s=7 TeV during 2011, corresponding to an integrated luminosity of 4.98 fb-1. The analysis is based on final states with a single lepton, b-quark jets, and missing transverse energy. Standard model yields are predicted from data using two different approaches. The observed event numbers are found to be compatible with these predictions. Results are interpreted in the context of the constrained minimal supersymmetric standard model and of a simplified model with four top quarks in the final state. © 2013 CERN.
Resumo:
Measurements of two- and four-particle angular correlations for charged particles emitted in pPb collisions are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 31nb-1, were collected during the 2013 LHC pPb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. The results are compared to 2.76 TeV semi-peripheral PbPb collision data, collected during the 2011 PbPb run, covering a similar range of particle multiplicities. The observed correlations are characterized by the near-side (|δφ|≈0) associated pair yields and the azimuthal anisotropy Fourier harmonics (vn). The second-order (v2) and third-order (v3) anisotropy harmonics are extracted using the two-particle azimuthal correlation technique. A four-particle correlation method is also applied to obtain the value of v2 and further explore the multi-particle nature of the correlations. Both associated pair yields and anisotropy harmonics are studied as a function of particle multiplicity and transverse momentum. The associated pair yields, the four-particle v2, and the v3 become apparent at about the same multiplicity. A remarkable similarity in the v3 signal as a function of multiplicity is observed between the pPb and PbPb systems. Predictions based on the color glass condensate and hydrodynamic models are compared to the experimental results. © 2013 CERN.
Resumo:
Results are presented from a search for the rare decays Bs0→μ+μ- and B0→μ+μ - in pp collisions at √s=7 and 8 TeV, with data samples corresponding to integrated luminosities of 5 and 20 fb-1, respectively, collected by the CMS experiment at the LHC. An unbinned maximum-likelihood fit to the dimuon invariant mass distribution gives a branching fraction B(Bs0→μ+μ-)=(3.0-0.9+1.0) ×10-9, where the uncertainty includes both statistical and systematic contributions. An excess of Bs0→μ+μ- events with respect to background is observed with a significance of 4.3 standard deviations. For the decay B0→μ+μ- an upper limit of B(B0→μ+μ-)<1.1×10 -9 at the 95% confidence level is determined. Both results are in agreement with the expectations from the standard model. © 2013 CERN. Published by the American Physical Society under the terms of the.
Resumo:
A search for supersymmetry is presented based on events with large missing transverse energy, no isolated electron or muon, and at least three jets with one or more identified as a bottom-quark jet. A simultaneous examination is performed of the numbers of events in exclusive bins of the scalar sum of jet transverse momentum values, missing transverse energy, and bottom-quark jet multiplicity. The sample, corresponding to an integrated luminosity of 19.4fb-1, consists of proton-proton collision data recorded at a center-of-mass energy of 8TeV with the CMS detector at the LHC in 2012. The observed numbers of events are found to be consistent with the standard model expectation, which is evaluated with control samples in data. The results are interpreted in the context of two simplified supersymmetric scenarios in which gluino pair production is followed by the decay of each gluino to an undetected lightest supersymmetric particle and either a bottom or top quark-antiquark pair, characteristic of gluino mediated bottom- or top-squark production. Using the production cross section calculated to next-to-leading-order plus next-to-leading-logarithm accuracy, and in the limit of a massless lightest supersymmetric particle, we exclude gluinos with masses below 1170GeV and 1020GeV for the two scenarios, respectively. © 2013 CERN.
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Pós-graduação em Engenharia Civil - FEIS
Resumo:
In Brazil, the entomological surveillance of Aedes (Stegomyia) aegypti is performed by government-mandated larval surveys. In this study, the sensitivities of an adult sticky trap and traditional surveillance methodologies were compared. The study was performed over a 12-week period in a residential neighbourhood of the municipality of Pedro Leopoldo, state of Minas Gerais, Brazil. An ovitrap and a MosquiTRAP were placed at opposite ends of each neighbourhood block (60 traps in total) and inspections were performed weekly. The study revealed significant correlations of moderate strength between the larval survey, ovitrap and MosquiTRAP measurements. A positive relationship was observed between temperature, adult capture measurements and egg collections, whereas precipitation and frequency of rainy days exhibited a negative relationship.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
A search for a Higgs boson decaying into a Z boson and a photon is described. The analysis is performed using proton-proton collision datasets recorded by the CMS detector at the LHC. Events were collected at center-of-mass energies of 7 TeV and 8 TeV, corresponding to integrated luminosities of 5.0 fb(-1) and 19.6 fb(-1), respectively. The selected events are required to have opposite-sign electron or muon pairs. No excess above standard model predictions has been found in the 120-160 GeV mass range and the first limits on the Higgs boson production cross section times the H -> Z gamma branching fraction at the LHC have been derived. The observed at 95% confidence level limits are between about 4 and 25 times the standard model cross section times the branching fraction. For a standard model Higgs boson mass of 125 GeV the expected limit at the 95% confidence level is 10 and the observed limit is 9.5. Models predicting the Higgs boson production cross section times the H -> Z gamma branching fraction to be larger than one order of magnitude of the standard model prediction are excluded for most of the 125-157 GeV mass range. (C) 2013 CERN. Published by Elsevier B.V. All rights reserved.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)