Reweighting Parton Showers
  We report on the possibility of reweighting parton-shower Monte Carlo predictions for scale variations in the parton-shower algorithm. The method is based on a generalization of the Sudakov veto algorithm. We demonstrate the feasibility of this approach using example physical distributions. Implementations are available for both the parton-shower modules in the Herwig 7 event generator. 
Johannes Bellm, Simon Pl\"atzer, Peter Richardson, Andrzej Si\'odmok,   Stephen Webster
hep-ph