A New Method for Computing Helicity Amplitudes
  An helicity formalism for perturbative calculations is presented. It is based on the formal insertion in spinor lines of a complete set of states built up with unphysical spinors. It is particularly convenient when massive spinors are present. Its application to $e^+\,e^-\,\rightarrow b\,\bar b\,W^+W^-$ is briefly discussed. 
A. Ballestrero and E. Maina