1,111 research outputs found

    Medida de la secci√≥n eficaz de producci√≥n de tZq en colisiones pp a ‚ąö8 =13TeV en CMS

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    Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física teórica. Fecha de Lectura: 13-06-2022This document presents a measurement of the production cross section of a single top quark in association with a Z boson (and an additional quark), a rare standard model process which is also an irreducible background to many important searches at the Large Hadron Collider (LHC). The process is studied using events with three leptons (electrons or muons) in the nal state for an integrated luminosity of 35:9 fb1 recorded by the Compact Muon Solenoid (CMS) detector at the LHC using proton-proton collisions at a centre-of-mass energy of 13 TeV. In these accelerator conditions, the reference next-to-leading-order (NLO) cross section for tZq ! Wb`+ q (considering only leptonic decays of the Z boson to electrons, muons or tau leptons) is 94:2+1:9 1:8 (scale) 2:5 (PDF) fb, which includes lepton pairs from o -shell Z bosons with invariant mass m`+ > 30 GeV. Previous analyses had been conducted at the LHC at 8 TeV but it was not until 2017, when the analysis described in this document was performed, that the rst evidence for this process was presented, also announced by the ATLAS collaboration in the same year. The evidence of this process along with a measurement of its cross section compatible with the prediction, represents an important test of the standard model. The nal state of the process is identical to avour-changing neutral current tZq production. Flavour-changing neutral currents (FCNC) are a phenomenon which is highly suppressed in the standard model, predicted to occur at rates that are not accessible at the current accelerator conditions. In fact, analyses looking for FCNC tZq signatures are conducted in parallel to tZq standard model searches by the experimental community. The cross section measurement presented is sensitive to the contribution from FCNC tZq production, were there incompatibilities with the theoretical standard model prediction. For this analysis, a multivariate classi cation approach is used to achieve a powerful discrimination between signal-like events and other standard model processes (background). The cross section is extracted from a maximum likelihood t performed simultaneously on three statistically independent regions for the four different leptonic channels (three electrons, three muons, two electrons and one muon, and one electron and two muons). The rst region is de ned to be populated mostly by signal events while the other two control regions are de ned so that they contain mostly events from the main background processes. The measurement yields a cross section value (pp ! tZq ! Wb`+`q) = 123+33 31 (stat) +29 23 (syst) fb, calculated so that it contains the contribution from tau leptons too. The observed (expected) signi cance is reported to be 3.7 (3.1) standard deviation

    Effectiveness of a strategy that uses educational games to implement clinical practice guidelines among Spanish residents of family and community medicine (e-EDUCAGUIA project):A clinical trial by clusters

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    This study was funded by the Fondo de Investigaciones Sanitarias FIS Grant Number PI11/0477 ISCIII.-REDISSEC Proyecto RD12/0001/0012 AND FEDER Funding.Background: Clinical practice guidelines (CPGs) have been developed with the aim of helping health professionals, patients, and caregivers make decisions about their health care, using the best available evidence. In many cases, incorporation of these recommendations into clinical practice also implies a need for changes in routine clinical practice. Using educational games as a strategy for implementing recommendations among health professionals has been demonstrated to be effective in some studies; however, evidence is still scarce. The primary objective of this study is to assess the effectiveness of a teaching strategy for the implementation of CPGs using educational games (e-learning EDUCAGUIA) to improve knowledge and skills related to clinical decision-making by residents in family medicine. The primary objective will be evaluated at 1 and 6months after the intervention. The secondary objectives are to identify barriers and facilitators for the use of guidelines by residents of family medicine and to describe the educational strategies used by Spanish teaching units of family and community medicine to encourage implementation of CPGs. Methods/design: We propose a multicenter clinical trial with randomized allocation by clusters of family and community medicine teaching units in Spain. The sample size will be 394 residents (197 in each group), with the teaching units as the randomization unit and the residents comprising the analysis unit. For the intervention, both groups will receive an initial 1-h session on clinical practice guideline use and the usual dissemination strategy by e-mail. The intervention group (e-learning EDUCAGUIA) strategy will consist of educational games with hypothetical clinical scenarios in a virtual environment. The primary outcome will be the score obtained by the residents on evaluation questionnaires for each clinical practice guideline. Other included variables will be the sociodemographic and training variables of the residents and the teaching unit characteristics. The statistical analysis will consist of a descriptive analysis of variables and a baseline comparison of both groups. For the primary outcome analysis, an average score comparison of hypothetical scenario questionnaires between the EDUCAGUIA intervention group and the control group will be performed at 1 and 6months post-intervention, using 95% confidence intervals. A linear multilevel regression will be used to adjust the model. Discussion: The identification of effective teaching strategies will facilitate the incorporation of available knowledge into clinical practice that could eventually improve patient outcomes. The inclusion of information technologies as teaching tools permits greater learning autonomy and allows deeper instructor participation in the monitoring and supervision of residents. The long-term impact of this strategy is unknown; however, because it is aimed at professionals undergoing training and it addresses prevalent health problems, a small effect can be of great relevance. Trial registration: ClinicalTrials.gov: NCT02210442.Publisher PDFPeer reviewe

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

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function √į√į¬•with constraints√į √į √į¬• ¬• √įand√į¬ī√į¬• = √į. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV