15-20 June 2014
Laurentian University / Université Laurentienne
America/Toronto timezone
Welcome to the 2014 CAP Congress! / Bienvenue au congrès de l'ACP 2014!

Measurement of the top quark polarization in semi-leptonically decaying top-antitop pairs with the ATLAS detector

16 Jun 2014, 14:30
C-112 (Laurentian University / Université Laurentienne)


Laurentian University / Université Laurentienne

Sudbury, Ontario
Oral (Student, Not in Competition) / Orale (Étudiant(e), pas dans la compétition) Particle Physics / Physique des particules (PPD) (M1-4) Energy Frontier: Standard Model and Higgs - PPD / Frontière d'énergie: modèle standard et boson de Higgs - PPD


Garrin Mcgoldrick (University of Toronto (CA))


The Standard Model predicts that top-antitop pairs produced through the strong interaction will have zero net longitudinal polarization due to parity conservation. Physics beyond the Standard Model could allow for non-parity conserving top-antitop pair production which would produce a net polarization signal at the Large Hadron Collider. I will present a measurement of the average polarization of top-antitop pairs decaying to the lepton plus jets final state as measured by the ATLAS detector at a centre of mass energy of sqrt(s) = 8 TeV. Events passing selection criteria expected of top-antitop pairs decaying to two b-quarks jets, two light quark jets, a lepton (electron or muon) and a neutrino, are included in the measurement. The measured jets, lepton and missing transverse energy are used as inputs to a kinematic fit which solves for the 4-momentum of the neutrino, which is not detected. The polarization can then be extracted from the distribution of angles formed between the lepton and leptonically decaying top quark in that quark's rest frame.

Primary author

Garrin Mcgoldrick (University of Toronto (CA))


Matthew Scott Rudolph (University of Toronto (CA))

Presentation Materials