# Herwig 7 Tutorials¶

## Bootstrap installation¶

To ensure a consistent and working setup, we highly recommend that you install Herwig and all its dependencies using the bootstrap script we provide.

## Manual installation¶

Should the options provided by the bootstrap script be insufficient for your purposes, or if a manual installation is required for a different reason, we provide detailed instructions below:

## Getting started¶

Your first run of Herwig. Look at a simple event and understand the event record.

Have a first look at the Herwig input files and understand their structure.

Switch on and off parts of the simulation like the hadronization or the underlying event simulation.

Select a different matrix element or only parts of an NLO simulation.

Using matrix elements from external providers. Also, how to set individual particles stable.

## Event generation workflow¶

Running event generation with Herwig is organized in two basic steps. For more complex processes several layers of parallelization and intermediate modifications have been added:

Herwig supports the input of external event files, and features various possibilities to store and analyse generated events:

## Hard cross sections and matching¶

The calculation of hard cross sections and their matching to fixed-order calculations is possible through a limited number of builtin processes, and in a more general fashion through use of the Matchbox framework, which is able to provide NLO matched simulations for both shower modules.

## Merging with the dipole shower¶

Building on the Matchbox framework a merging algorithm for combining multijet NLO QCD calculations with the dipole shower is available

## Showers¶

Herwig provides two shower modules. By default, the angular ordered shower will be used, and as an alternative, a dipole-type showering algorithm is provided.

In addition the multiple-scattering model of the underlying event takes place as part of the parton shower in Herwig, see the next section.

## Multiple-Parton Interactions¶

The multiple-scattering model of the underlying event uses multiple partonic-scattering processes in order to simulate the underlying event.

## Beyond the Standard Model simulation¶

A number of models of physics beyond the Standard Model (BSM) of particle physics are included in Herwig. In addition a large number of further models can be used via our interface to models written in the Universal FeynRules Output (UFO) format.

## Decays¶

Herwig includes a sophisticated internal model for hadronic decays with a focus on the simulation of the decays of the light hadrons, including baryons. Starting with Herwig 7.1 we therefore provide a interface to the EvtGen package for a simulation of B-hadron decays which is more tuned to B-factory data.

## Contrib¶

Several projects build on the Herwig infrastructure and are contained in the Contrib folder of the Herwig source directory.