Measurement of the Underlying Event at Tevatron
Deepak Kar
TL;DR
The paper addresses how to accurately model the underlying event in hadron collisions by analyzing Drell-Yan–related UE at the Tevatron and comparing the data to QCD Monte-Carlo models. It uses Z-boson events to probe the UE across regions relative to the lepton-pair direction and tunes MC predictions (notably PYTHIA AW) to data, highlighting the role of MPI. The results indicate that MPI contributions are essential for reproducing observed multiplicities and momentum densities, with some universality suggested by agreement with leading-jet UE studies. The findings support tuning strategies for UE at the LHC and stress the importance of energy-dependent UE modeling for future high-energy colliders.
Abstract
CDF Run II data for the underlying event associated with Drell-Yan lepton pair production are examined as a function of the lepton-pair transverse momentum. The data are compared with a previous analysis on the behavior of the underlying event in high transverse momentum jet production and also with several other QCD Monte-Carlo models. The goal is to provide data that can be used to tune and improve the QCD Monte-Carlo models of the underlying event, which is especially important now in view of the LHC startup.