NLO matrix elements and truncated showers

TL;DR

This paper introduces an algorithm that merges NLO matrix elements with parton showers, enhancing the accuracy of event simulations across various high-energy physics processes, and is implemented in the Sherpa generator.

Contribution

It presents a novel algorithm combining ME+PS and POWHEG methods, implemented in Sherpa, to improve event simulation accuracy for multiple processes.

Findings

First predictions for jet production in various processes

Demonstrates improved accuracy over previous methods

Applicable to collider physics simulations

Abstract

In this publication, an algorithm is presented that combines the ME+PS approach to merge sequences of tree-level matrix elements into inclusive event samples with the POWHEG method, which combines exact next-to-leading order matrix element results with the parton shower. It was developed in parallel to the MENLOPS technique and has been implemented in the event generator Sherpa. The benefits of this approach are exemplified by some first predictions for a number of processes, namely the production of jets in e+ e- annihilation, in deep-inelastic ep scattering, in association with single W, Z or Higgs bosons, and with vector boson pairs at hadron colliders.