Multiple Partonic Interaction Developments in Herwig++

Abstract

We briefly review the status of the multiple partonic interaction model in the Herwig++ event generator. First, we show how a change in the colour structure of an event in Herwig++ results in a significant improvement in the description of soft inclusive observables in $pp$ interactions at $\sqrt{s}=900$ GeV. Then we present a comparison of some model results to ATLAS Underlying Event data at $\sqrt{s}=7$ TeV.

Comments: 9 pages, 5 figures. To appear in the proceedings of the MPI@LHC 2010: 2nd International Workshop on Multiple Partonic Interactions at the LHC, Glasgow, 29th of November to the 3rd of December 2010