Pythia Tune A, Herwig, and Jimmy in Run 2 at CDF
  We study the behavior of the charged particle and energy components of the "underlying event" in hard scattering proton-antiproton collisions at 1.96TeV. The goal is to produce data on the "underlying event" that is corrected to the particle level so that it can be used to tune the QCD Monte-Carlo models without requiring CDF detector simulation. Unlike the previous CDF Run 2 "underlying event" analysis which used JetClu to define "jets" and compared uncorrected data with the QCD Monte-Carlo models after detector simulation (i.e., CDFSIM), this analysis uses the MidPoint jet algorithm and corrects the observables to the particle level. The corrected observables are then compared with the QCD Monde-Carlo models at the particle level (i.e., generator level). The QCD Monte-Carlo models include PYTHIA Tune A, HERWIG, and a tuned version of JIMMY. 
Rick Field, R. Craig Group