UNSPECIFIED (2012) Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at s√=7 TeV with the ATLAS experiment. European Physical Journal C: Particles and Fields, 72 (5): 2001. ISSN 1434-6044
art_3A10.1140_2Fepjc_2Fs10052_012_2001_6.pdf - Published Version
Available under License Creative Commons Attribution.
Download (2MB)
Abstract
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 f 0, f L and f R 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 f 0 and f L−f R, averaged over charge and lepton flavour, are measured to be: f 0=0.127±0.030±0.108 and f L−f R=0.252±0.017±0.030, where the first uncertainties are statistical, and the second include all systematic effects.