Dresden 2013 – scientific programme

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T: Fachverband Teilchenphysik

T 15: Beyond the Standard Model (Theorie) 2

T 15.3: Talk

Monday, March 4, 2013, 17:15–17:30, WIL-A124

Anomalous Top Couplings in WHIZARD — •Fabian Bach and Thorsten Ohl — Institut für Theoretische Physik und Astrophysik, Universität Würzburg

Because of its natural Yukawa coupling strength and corresponding large mass, the top quark plays a special role not only in the SM, but also as a window to new physics in many of its extensions. At the LHC, large abundances of top quarks are being produced, providing the statistics necessary to measure various properties of the top quark with high precision. Using effective field theory, it is possible to parameterize any new physics contributing to top interactions via anomalous top quark-gauge boson couplings ttγ, ttZ, tbW and ttg, while contact terms (e. g. ttgg) have to be included in general to ensure gauge invariance. The full gauge-invariant set of operators leading to anomalous trilinear top couplings has been implemented into the parton-level Monte Carlo generator Whizard to provide a comprehensive tool for MC studies of the complete hard scattering amplitudes including decays of top quarks and heavy gauge bosons as well as all irreducible backgrounds. We show results for single top production with anomalous tbW couplings, and argue that it is necessary to go to full matrix elements including anomalous top decays to properly account for the coupling dependence of the cross sections at detector level.