8 research outputs found

    Evidence of off-shell Higgs boson production from ZZ leptonic decay channels and constraints on its total width with the ATLAS detector

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    This Letter reports on a search for off-shell production of the Higgs boson using 139 fb−1 of pp collision data at √s = 13 TeV collected by the ATLAS detector at the Large Hadron Collider. The signature is a pair of Z bosons, with contributions from both the production and subsequent decay of a virtual Higgs boson and the interference of that process with other processes. The two observable final states are Z Z → 4 and Z Z → 22ν with = e or μ. In the Z Z → 4 final state, a dense Neural Network is used to enhance analysis sensitivity with respect to matrix element-based discrimination. The backgroundonly hypothesis is rejected with an observed (expected) significance of 3.3 (2.2) standard deviations, representing experimental evidence for off-shell Higgs boson production. Assuming that no new particles enter the production of the virtual Higgs boson, its total width can be deduced from the measurement of its off-shell production cross-section. The measured total width of the Higgs boson is 4.5+3.3 −2.5 MeV, and the observed (expected) upper limit on the total width is found to be 10.5 (10.9) MeV at 95% confidence level

    Determination of the strong coupling constant from transverse energy-energy correlations in multijet events at s√ = 13 TeV with the ATLAS detector

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    Measurements of transverse energy-energy correlations and their associated azimuthal asymmetries in multijet events are presented. The analysis is performed using a data sample corresponding to 139 fb−1 of proton-proton collisions at a centre-of-mass energy of s√ = 13 TeV, collected with the ATLAS detector at the Large Hadron Collider. The measurements are presented in bins of the scalar sum of the transverse momenta of the two leading jets and unfolded to particle level. They are then compared to next-to-next-to-leading-order perturbative QCD calculations for the first time, which feature a significant reduction in the theoretical uncertainties estimated using variations of the renormalisation and factorisation scales. The agreement between data and theory is good, thus providing a precision test of QCD at large momentum transfers Q. The strong coupling constant αs is extracted as a function of Q, showing a good agreement with the renormalisation group equation and with previous analyses. A simultaneous fit to all transverse energy-energy correlation distributions across different kinematic regions yields a value of αs(mZ)=0.1175±0.0006(exp.)+0.0034−0.0017(theo.) , while the global fit to the asymmetry distributions yields αs(mZ)=0.1185±0.0009(exp.)+0.0025−0.0012(theo.)

    Genetic variability and pedigree analysis of Brazilian common bean elite genotypes Variabilidade genética e análise de pedigree em genótipos elite brasileiros de feijoeiro comum

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    Genetic diversity is essential for any breeding program. However, breeders tend to concentrate on specific genotypes, which combine traits of interest and may be used as progenitors in several breeding programs. Common bean (Phaseolus vulgaris L.) breeding programs are not different in this sense. In this study, the genetic diversity of 21 common bean elite lines from the Bean Regional Trials conducted by the Embrapa Rice and Bean Research Center was evaluated using the Random Amplified Polymorphic DNA (RAPD) and pedigree analyses. Based on genetic dissimilarity, three groups were defined: group I - lines 1, 9 and 10, with low genetic distances among them (0.00 to 0.06), originated from 11 Mesoamerican parents; group II - 17 lines with genetic distances ranging from 0.03 to 0.33, originated from 50 parents (mostly Mesoamerican); and group III - line 21 (PR 93201472), which parents are the Andean cultivar 'Pompadour' and the cultivar 'Irai' (unknown origin). The genetic distances between line 21 and the lines of the other two groups varied from 0.68 to 0.93. Pedigree analyses demonstrated that cultivars 'Carioca', 'Cornell 49-242', 'Jamapa', 'Tlalnepantla 64', 'Tara' and 'Veranic 2', all of Mesoamerican origin, were the most widely used parents for developing lines present in group II.<br>Diversidade genética é um pré-requisito em qualquer tipo de programa de melhoramento. No entanto, os melhoristas tendem a se concentrar em alguns genótipos que reúnem características de interesse e estes são usados em diversos programas de melhoramento. Os programas de melhoramento do feijoeiro (Phaseolus vulgaris L.) não são diferentes quanto a esse aspecto. Visando o estudo da variabilidade genética, 21 cultivares-elite dos Ensaios Regionais de Feijão coordenados pela Embrapa Arroz e Feijão, foram caracterizados com marcadores moleculares Random Amplified Polymorphic DNA (RAPD). Também, os pedigrees dos 21 cultivares elite foram pesquisados com o objetivo de estudar os progenitores usados no seu desenvolvimento. Baseado nos dados de distância genética, um gráfico de dispersão foi construído e três grupos foram identificados: 1) grupo I, formado pelas linhas 1, 9 e 10, com baixa diversidade genética entre si (0,00 a 0,06), originadas de 11 progenitores de origem Mesoamericana; 2) grupo II, formado por 17 linhagens com distâncias genéticas variando de 0,03 a 0,33, originadas de 50 progenitores, a maioria de origem Mesoamericana; e, 3) grupo III, formado pelo cultivar PR 93201472 (linhagem 21), que tem os cultivares 'Pompadour' (origem Andina) e 'Irai' (origem desconhecida) como seus progenitores. As distâncias genéticas entre PR 93201472 e os outros 20 cultivares variaram entre 0,68 e 0,93. De acordo com seus pedigrees, os cultivares 'Carioca', 'Cornell 49-242', 'Jamapa', 'Tlalnepantla 64', 'Tara' e 'Veranic 2', todos de origem Mesoamericana, foram os progenitores mais empregados na geração das linhagens do grupo II

    Body mass index and complications following major gastrointestinal surgery: A prospective, international cohort study and meta-analysis

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    Aim Previous studies reported conflicting evidence on the effects of obesity on outcomes after gastrointestinal surgery. The aims of this study were to explore the relationship of obesity with major postoperative complications in an international cohort and to present a metaanalysis of all available prospective data. Methods This prospective, multicentre study included adults undergoing both elective and emergency gastrointestinal resection, reversal of stoma or formation of stoma. The primary end-point was 30-day major complications (Clavien–Dindo Grades III–V). A systematic search was undertaken for studies assessing the relationship between obesity and major complications after gastrointestinal surgery. Individual patient meta-analysis was used to analyse pooled results. Results This study included 2519 patients across 127 centres, of whom 560 (22.2%) were obese. Unadjusted major complication rates were lower in obese vs normal weight patients (13.0% vs 16.2%, respectively), but this did not reach statistical significance (P = 0.863) on multivariate analysis for patients having surgery for either malignant or benign conditions. Individual patient meta-analysis demonstrated that obese patients undergoing surgery formalignancy were at increased risk of major complications (OR 2.10, 95% CI 1.49–2.96, P < 0.001), whereas obese patients undergoing surgery for benign indications were at decreased risk (OR 0.59, 95% CI 0.46–0.75, P < 0.001) compared to normal weight patients. Conclusions In our international data, obesity was not found to be associated with major complications following gastrointestinal surgery. Meta-analysis of available prospective data made a novel finding of obesity being associated with different outcomes depending on whether patients were undergoing surgery for benign or malignant disease
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