Interleaved Parton Showers and Tuning Prospects

TL;DR

This paper evaluates and improves the Pythia 8 Monte Carlo generator's parton-shower algorithms, introducing new features, comparing with QCD matrix elements, and tuning to Tevatron and LHC data for better particle physics simulations.

Contribution

It introduces new code features in Pythia 8, compares shower algorithms with QCD matrix elements, and performs tuning to collider data to enhance simulation accuracy.

Findings

Enhanced description of data with new code features

Good agreement between shower algorithms and matrix elements

Successful tuning to Tevatron and LHC data

Abstract

General-purpose Monte Carlo event generators have become important tools in particle physics, allowing the simulation of exclusive hadronic final states. In this article we examine the Pythia 8 generator, in particular focusing on its parton-shower algorithms. Some relevant new additions to the code are introduced, that should allow for a better description of data. We also implement and compare with 2 to 3 real-emission QCD matrix elements, to check how well the shower algorithm fills the phase space away from the soft and collinear regions. A tuning of the generator to Tevatron data is performed for two PDF sets and the impact of first new LHC data is examined.