Towards pair production near threshold with unstable particle effective   theory
  We illustrate the use of effective theory techniques to describe processes involving unstable particles close to resonance. First, we present the main ideas in the context of a scalar resonance in an Abelian gauge-Yukawa model. We then outline the necessary modifications to describe W-pair production close to threshold in electron-positron collisions. 
M.Beneke, N.Kauer, A.Signer, G.Zanderighi