895 research outputs found

    Extracting the top-quark running mass using ttˉt\bar{t}+1-jet events produced at the Large Hadron Collider

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    We present the calculation of the next-to-leading order QCD corrections for top-quark pair production in association with an additional jet at hadron colliders, using the modified minimal subtraction scheme to renormalize the top-quark mass. The results are compared to measurements at the Large Hadron Collider run I. In particular, we determine the top-quark running mass from a fit of the theoretical results presented here to the LHC data

    Experimental prospects for precision observables in ee+qqˉe^{-}e^{+}\rightarrow q\bar{q} with q=b,cq=b,c processes at the ILC operating at 250 and 500 GeV of center of mass

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    Future Higgs Factories will allow the precise study of ee+qqˉe^{-}e^{+}\rightarrow q\bar{q} with q=s,c,b,tq=s,c,b,t interactions at different energies, from the Z-pole up to high energies never reached before. In this contribution, we will discuss the experimental prospects for the measurement of differential observables in ee+bbˉe^{-}e^{+}\rightarrow b\bar{b} and ee+ccˉe^{-}e^{+}\rightarrow c\bar{c} processes at high energies, 250 and 500 GeV, using full simulation samples and the full reconstruction chain from the ILD concept group. These processes call for superb primary and secondary vertex measurements, a high tracking efficiency to correctly measure the vertex charge and excellent hadron identification capabilities using dE/dxdE/dx. This latter aspect will be discussed in detail together with its implementation within the standard flavour tagging tools developed for ILD (LCFI+). In addition, prospects associated with potential improvements using cluster counting techniques instead of traditional dE/dxdE/dx will be discussed.Comment: This work was carried out in the framework of the ILD concept group. Talk presented at the International Workshop on Future Linear Colliders (LCWS 2023), 15-19 May 2023. C23-05-15.

    Sistemas de protección individual anticaídas sometidos a impacto. Simulaciones numéricas

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    Personal fall protection systems are set up by EN-363 to avoid or retain people falls safely (without relevant damages). They are the ultimate resource to prevent a fall after other measures being considered. This paper analyses the variables affecting the system behaviour: free fall height, length of retaining rope, stiffness and damping of retaining material, and worker weight. To this end, fall phenomenon has been simulated with finite elements dynamic models with an elastic rope and a rigid ballast. It allows obtain likely values of maximum forces on the injured and over the system during the impact. Results demonstrate the fundamental role of height fall vs. rope length rate (fall factor), which results more important than the fall height itself. The severe values obtained for maximum forces show that future research would include elastoplastic energy absorbers to decrease impact until reasonable values.Los sistemas anticaída se establecen en UNE-EN-363 para evitar o retener caídas de personas sin que las fuerzas de retención causen daños relevantes. Constituyen el último recurso para prevención de caídas tras considerar otras medidas. Este artículo analiza las variables que afectan al comportamiento del sistema: altura de caída, longitud de cuerda de retención, rigidez y amortiguamiento del material de retención, y peso del operario. A tal fin, el fenómeno ha sido simulado con modelos dinámicos de elementos finitos mediante una cuerda elástica y un lastre rígido. Ello permite obtener valores verosímiles de las máximas fuerzas sobre el accidentado y el sistema durante el impacto. Los resultados demuestran el papel fundamental de la proporción entre altura de caída y longitud de cuerda (factor de caída), más determinante que la propia altura de caída. Las elevadas fuerzas máximas obtenidas indican la necesidad de incluir en el modelo absorbedores de energía elastoplásticos, en futuras investigaciones, con el fin de disminuir el impacto a valores razonables

    Shower development of particles with momenta from 15 GeV to 150 GeV in the CALICE scintillator-tungsten hadronic calorimeter

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    We present a study of showers initiated by electrons, pions, kaons, and protons with momenta from 15 GeV to 150 GeV in the highly granular CALICE scintillator-tungsten analogue hadronic calorimeter. The data were recorded at the CERN Super Proton Synchrotron in 2011. The analysis includes measurements of the calorimeter response to each particle type as well as measurements of the energy resolution and studies of the longitudinal and radial shower development for selected particles. The results are compared to Geant4 simulations (version 9.6.p02). In the study of the energy resolution we include previously published data with beam momenta from 1 GeV to 10 GeV recorded at the CERN Proton Synchrotron in 2010.Comment: 35 pages, 21 figures, 8 table

    Análisis de la relevancia y factibilidad de indicadores de calidad en las unidades de nutrición

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    Introducción: La evaluación de la calidad en las actividades sanitarias exige la elección de unos indicadores acordes con los resultados que queremos medir. De todos los posibles, debemos priorizar aquellos que nos permitan obtener la información más relevante sin sobrecargar el trabajo habitual de nuestras Unidades. Objetivo: Conocer la opinión de los socios de SENPE respecto a la relevancia y la viabilidad del uso de una selección de indicadores de calidad para su aplicación en nutrición clínica. Métodos: Encuesta remitida mediante correo electrónico a los socios de SENPE solicitando a los mismos su opinión sobre 12 indicadores de calidad, valorándose cada uno en cuanto a su relevancia y factibilidad de la aplicación en su medio. Resultados: Contestaron 40 encuestados de 40 centros diferentes de 12 comunidades autónomas. En general, los indicadores fueron considerados más relevantes que factibles. Los indicadores mejor puntuados fueron: “identificación en las bolsas de nutrición artificial”, “posición semi-incorporada del paciente con nutrición enteral por sonda nasogástrica” y “protocolos clínicos básicos”. Considerando los indicadores por grupos (de estructura, proceso o resultado) los mejor valorados fueron: “identificación del paciente en las bolsas de nutrición artificial” (estructura), “posición semi-incorporada” y “protocolos clínicos básicos” (proceso), y “cumplimiento del objetivo calórico” (resultado). Conclusión: Los resultados de la encuesta permiten seleccionar indicadores prioritarios para su aplicación en las Unidades de NutriciónIntroduction: The quality assessment in health activities requires the choice of indicators in line with the results we want to measure. Of all possible, we should prioritize those that allow us to obtain the most relevant information without overloading the regular work of our units. Objective: To determine the opinion of the members of SENPE regarding the relevance and feasibility of using a selection of quality indicators designed for use in clinical nutrition. Methods: E-mail survey sent to members of SENPE asking them their views on 12 quality indicators, evaluating each in terms of their relevance and feasibility of implementation in their environment. Results: 40 respondents answered from 40 centers in 12 different regions. In general, the indicators were considered more relevant than feasible. The indicators best rated were: “identification in artificial nutrition bags, “semi-recumbent position in patient with nasogastric tube feeding” and “basic clinical protocols”. Considering the type of indicator: “patient identification in the bags of artificial nutrition (structure),” a semi-incorporated “and” basic clinical protocols (process), and “fulfillment of the caloric goal” (result). Conclusion: The results of the survey can make a selection of indicators that could be considered for first-line introduction in a Nutrition Uni

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Hadron shower decomposition in the highly granular CALICE analogue hadron calorimeter

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    The spatial development of hadronic showers in the CALICE scintillator-steel analogue hadron calorimeter is studied using test beam data collected at CERN and FNAL for single positive pions and protons with initial momenta in the range from 10 to 80 GeV/c. Both longitudinal and radial development of hadron showers are parametrised with two-component functions. The parametrisation is fit to test beam data and simulations using the QGSP_BERT and FTFP_BERT physics lists from Geant4 version 9.6. The parameters extracted from data and simulated samples are compared for the two types of hadrons. The response to pions and the ratio of the non-electromagnetic to the electromagnetic calorimeter response, h/e, are estimated using the extrapolation and decomposition of the longitudinal profiles.Comment: 38 pages, 19 figures, 5 tables; author list changed; submitted to JINS

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30
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