Measurement of angular correlations to probe Z/γ∗ boson transverse momentum - An ideal test of pQCD -

by Dr Thi Kieu Oanh DOAN (Annecy (LAPP))

Monday 10 Jun 2013, 11:00 → 12:00 Europe/Brussels

Large seminar room (IIHE (ULB-VUB))

Abstract: The angular correlations in Drell-Yan electron pairs are presented in a form of an observable φη∗ . It probes the same physics as the Z/γ∗ boson transverse momentum with a better experimental resolution. The results of the first measurement of the φη∗ spectrum at LHC 7 TeV pp collisions are introduced here, which were published in the ATLAS paper Phys. Lett. B 720 (2013) 32-51. The normalised differential cross section as a function of φη∗ was measured and compared to QCD calculations and to predictions from different Monte Carlo event generators. The measurement precision is typically better by one order of magnitude than present theoretical uncertainties and therefore is valuable to constrain theoretical predictions further. The dominant uncertainty of this measurement is due to φη∗-dependent modelling of QED Final State Radiation corrections. An independent study of this uncertainty was published in arXiv:1303.2220 [hep-ph] and is also introduced here. The level of this uncertainty was cross-checked and the structure of this uncertainty was understood.