test

Simulation of a dijet production event at the LHC for 7 TeV center-of-mass energy, using the [[ https://rivet.hepforge.org/analyses/ATLAS_2012_I1082936.html | ATLAS_2012_I1082936 ]] Rivet plugin for data analysis. Please download the following input file and move it to your work directory: Input file: {F542868} 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 [[ https://phab.hepforge.org/w/mcnet2019/leshouches/ | 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.