A measurement of the top quark electric charge is carried out in the ATLAS experiment at the Large Hadron Collider using 2.05 fb −1 of data at a centre-of-mass energy of 7 TeV. In units of the elementary electric charge, the top quark charge is determined to be 0.64 ± 0.02 (stat.) ± 0.08 (syst.) from the charges of the top quark decay products in single lepton tt candidate events. This excludes models that propose a heavy quark of electric charge -4/3, instead of the Standard Model top quark, with a significance of more than 8σ. The ATLAS collaboration 26 IntroductionIt is generally accepted that the particle discovered at Fermilab in 1995 [1,2] is the Standard Model (SM) top quark. However, a few years after the discovery a theoretical model appeared proposing an "exotic" quark of charge -4/3 and mass ≈ 170 GeV as an alternative to the SM top quark at this mass value [3]. Though this model has already been experimentally excluded a precise measurement of the top quark charge is important as it is one of the basic top quark properties. A strong preference for the SM top quark with electric charge of +2/3 (in units of the electron charge magnitude) was reported by the D0 and CDF collaborations [4,5] but without the ultimate 5σ exclusion of a possible exotic quark with charge of -4/3. The CDF and D0 exclusion limits are 95% 1 and 92%, 1 The CDF collaboration has recently submitted an update of their analysis for publication, which results in a limit of 99% [6].-1 - JHEP11(2013)031respectively. Therefore, it is still important to carry out a more precise measurement to definitively resolve this question with more than 5σ confidence level. Due to the excellent ATLAS detector performance, the analysis presented here not only demonstrates that the particle presently denoted by "top quark" is really the SM top quark decaying into a bquark and a W + boson, but also allows for a direct measurement of its electric charge with a significantly improved precision. Moreover, from an experimental point of view it is interesting to demonstrate the high flavour tagging performance of the ATLAS experiment, i.e. its capability to distinguish between jets initiated by quarks and anti-quarks used in this study to find the correct W b pairing in the W + W − bb system of the assumed tt final state.The dominant decay channel of the top quark is to a b-quark through the charged weak current: t → W + b (t → W −b ). The measurement of the top quark charge requires the charges of both the W boson and the b-quark to be determined. While the former can be determined through W's leptonic decay, the b-quark charge is not directly measurable due to quark confinement in hadrons. However, it is possible to establish a correlation between the charge of the b-quark and the charges of the collimated hadrons from the bquark hadronization that form a b-jet. Within this approach, the charge can be determined using the lepton + jets (tt → ℓ ± νjjbb) or the dilepton (tt → ℓ + νℓ −ν bb) channel. This paper presents the results of a top quark cha...
Data on sepsis in patients with a subarachnoid hemorrhage (SAH) are scarce. We assessed the impact of different sepsis criteria on the outcome in an SAH cohort. Adult patients admitted to our ICU with a spontaneous SAH between 11/2014 and 11/2018 were retrospectively included. In patients developing an infection, different criteria for sepsis diagnosis (Sepsis-1, Sepsis-3_original, Sepsis-3_modified accounting for SAH-specific therapy, alternative sepsis criteria compiled of consensus conferences) were applied and their impact on functional outcome using the modified Rankin Scale (mRS) on hospital discharge and in-hospital mortality was evaluated. Of 270 SAH patients, 129 (48%) developed an infection. Depending on the underlying criteria, the incidence of sepsis and septic shock ranged between 21–46% and 9–39%. In multivariate logistic regression, the Sepsis-1 criteria were not associated with the outcome. The Sepsis-3 criteria were not associated with the functional outcome, but in shock with mortality. Alternative sepsis criteria were associated with mortality for sepsis and in shock with mortality and the functional outcome. While Sepsis-1 criteria were irrelevant for the outcome in SAH patients, septic shock, according to the Sepsis-3 criteria, adversely impacted survival. This impact was higher for the modified Sepsis-3 criteria, accounting for SAH-specific treatment. Modified Sepsis-3 and alternative sepsis criteria diagnosed septic conditions of a higher relevance for outcomes in patients with an SAH.
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