A new look at the Wtb vertex using Fourier techniques in single top events at ATLAS

par Prof. Joe Boudreau (Pittsburgh)

lundi 20 nov. 2017, 14:00 → 15:00 Europe/Paris

The decay of the top quark to a bottom quark and a \emph{W} boson is governed by the Wtb vertex, which can be described by a few complex parameters of an effective Lagrangian that may reveal new physics at a higher mass scale. Using a sample of polarized single top quarks produced in 8 TeV collisions, the ATLAS collaboration has undertaken a complete analysis of the Wtb vertex by analyzing the triple-differential angular rate of top quark decays. The analysis yields new information on decay amplitudes and phases in the $t\rightarrow Wb$ transition, or, in an alternate formulation, constraints on anomalous couplings at the Wtb vertex. The analysis techniques are novel and include an angular variant of the ordinary convolution theorem to remove resolution effects of the ATLAS detector. We discuss results from the 8 TeV analysis and possible extensions to present and future datasets.