Measurement of the top quark mass with the template method in the t(t)over-bar -> lepton plus jets channel using ATLAS data

• Main Author: Onofre, A.
• Publication Date: 2012
• Other Authors: Castro, Nuno Filipe Silva Fernandes, ATLAS Collaboration
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/1822/48844
• topic: Ciências Naturais::Ciências Físicas; Ciências Naturais::Ciências Físicas; Science & Technology

This paper describes an analysis of the angular distribution of W→eν and W→μν decays, using data from pp collisions at s√=7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb−1. Using the decay lepton transverse momentum and the missing transverse momentum, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (pWT):35<pWT<50 GeV and pWT>50 GeV. Good agreement is found with theoretical predictions. For pWT>50 GeV, the values of f0 and fL−fR, averaged over charge and lepton flavour, are measured to be: f0=0.127±0.030±0.108 and fL−fR=0.252±0.017±0.030, where the first uncertainties are statistical, and the second include all systematic effects.