Single top quark production at LHC with anomalous Wtb couplings

Understand

We investigate single top production in the presence of anomalous Wtb couplings.

• We explicitly show that, if these couplings arise from gauge invariant effective operators, the only relevant couplings for single top production and decay are the usual gamma^mu and sigma^mu nu q_nu terms, where q is the W boson momentum.
• This happens even in the single top production processes where the Wtb interaction involves off-shell top and/or bottom quarks.
• With this parameterisation for the Wtb vertex, we obtain expressions for the dependence on anomalous couplings of the single top cross sections, for (i) the t-channel process, performing a matching between tj and t bbar j production, where j is a light jet; (ii) s-channel t bbar production; (iii) associated tW- production, including the correction from tW- bbar.