Min-Bias and the Underlying Event at the LHC

TL;DR

This paper evaluates the performance of different PYTHIA tunes in modeling the underlying event and minimum-bias data at the LHC, finding that Tune Z1 describes UE data well but no model captures all features of MB collisions.

Contribution

It provides a detailed comparison of PYTHIA Tune DW and Tune Z1 predictions against LHC data, highlighting their strengths and limitations.

Findings

Tune Z1 describes UE data at 900 GeV and 7 TeV well.

Neither model captures all features of min-bias collisions.

Both tunes describe Drell-Yan UE data effectively.

Abstract

The CDF PYTHIA 6.2 Tune DW predictions for the behavior of the LHC underlying event (UE) data at 900 GeV and 7 TeV are examined in detail. The behavior of the UE at the LHC is roughly what we expected. The LHC PYTHIA 6.4 Tune Z1 does an excellent job describing the UE data at 900 GeV and 7 TeV. Both Tune DW and Tune Z1 describe fairly well the Drell-Yan UE data at 1.96 TeV and 7 TeV. No model describes all the features of "min-bias" (MB) collisions at 900 GeV and 7 TeV.