Comparison of the full matrix element calculation with the simplified   calculation of the $W_R$ production at the LHC (left-right symmetric model)
  We estimate possible systematic error that can arise in the simplified simulation of the $W_R$ production and its subsequent decay into heavy neutrino at LHC (left-right symmetric model). The general-purpose event generators simulate this process as a $W_R$ production followed by two decays, loosing full information about the polarization of the intermediate particles. We calculate the cross section using the full matrix elements with propagators, perform the simulation and compare the results with the simplified simulation 
G. Bednik, M. Kirsanov
hep-ph