Tuning of PYTHIA6.4 to Minimum Bias and Underlying Event Data

QCD describes hadronic interactions quite well at large momentum transfers also known as hard interactions. However high energy hadron-hadron collisions are dominated by soft partonic collisions. Different phenomenological models are implemented in several Monte Carlo event generators such as PYTHIA PHOJET and HERWIG etc. which attempt to simulate these interactions. These MC event generators have free parameters which need to be tuned to improve the agreement with the data. PYTHIA6.4 Monte Carlo event generator is considered for optimization in this book using nine different Parton Density Functions.