Herwig 7.3 Release Note

TL;DR

Herwig 7.3 introduces significant enhancements including a process-independent electroweak parton shower, improved heavy quark modeling, and refined hadronization techniques, advancing the accuracy and flexibility of Monte Carlo event simulations.

Contribution

The paper presents the new features and improvements in Herwig 7.3, notably the electroweak angular-ordered shower, heavy quark effective theory integration, and advanced hadronization models.

Findings

Implementation of electroweak angular-ordered parton shower

Enhanced heavy meson and baryon decay modeling

New tuning of parton shower and hadronization parameters

Abstract

A new release of the Monte Carlo event generator Herwig (version 7.3) has been launched. This iteration encompasses several enhancements over its predecessor, version 7.2. Noteworthy upgrades include: the implementation of a process-independent electroweak angular-ordered parton shower integrated with QCD and QED radiation; a new recoil scheme for initial-state radiation improving the behaviour of the angular-ordered parton shower; the incorporation of the heavy quark effective theory to refine the hadronization and decay of excited heavy mesons and heavy baryons; a dynamic strategy to regulate the kinematic threshold of cluster splittings within the cluster hadronization model; several improvements to the structure of the cluster hadronization model allowing for refined models; the possibility to extract event-by-event hadronization corrections in a well-defined way; the possibility of using the string model, with a dedicated tune. Additionally, a new tuning of the parton shower and hadronization parameters has been executed. This article discusses the novel features introduced in version 7.3.0.