The Underlying Event in Herwig++
  We review the modelling of multiple interactions in the event generator Herwig++ and study implications of recent tuning efforts to LHC data. A crucial ingredient to a successful description of minimum-bias and underlying-event observables is a model for colour reconnection. Improvements to this model, inspired by statistical physics, are presented. 
Stefan Gieseke, Christian R\"ohr and Andrzej Si\'odmok
hep-ph