Second run: switching things on and off

Updated 1,757 Days AgoPublic

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Simulation of a dijet production event at the LHC for 7 TeV center-of-mass energy, using the ATLAS_2012_I1082936 Rivet plugin for data analysis.

Please download the following input file and move it to your work directory:

Input file:

Alternatively, you can use the following command-line codes:

mkdir LHC-dijet

cd LHC-dijet

wget https://phab-files.hepforge.org/file/download/eh5glykvcuwpul6yvwzp/PHID-FILE-g4u3mgzeahyqyc7mcgvj/LHC-dijet.in

You can run the dijey event, using

Herwig read LHC-dijet.in

You should see an error message appearing on your console

Error: MatchboxFactory: No matrix elements have been found.
      Please check if your order of Alpha_s and Alpha_ew have the right value.

This indicated that the Matchbox does not contain this specific process and you must use either an external matrix element (ME) provider of a Les Houches input file. Let us consider the former option at the moment. We will return to the Les Houches case later on.

There is a section in the input files for choosing the possible external ME providers:

##################################################
## Matrix element library selection
##################################################

## Select a generic tree/loop combination or a
## specialized NLO package

# read Matchbox/MadGraph-GoSam.in
# read Matchbox/MadGraph-MadGraph.in
# read Matchbox/MadGraph-NJet.in
# read Matchbox/MadGraph-OpenLoops.in

Please uncomment the "read Matchbox/MadGraph-OpenLoops.in" option. This would tell the event handler to use MadGraph and OpenLoops for the tree-level and one-loop MEs, respectively. You can see that there are a number of different options to choose from, based on the event that you want to simulate.