Particle electron api request tutorial5/17/2023 ![]() More details on the generate syntax can be found at Īn independent process can be added to the generation with, for example:Īdd process p p > w+ h, w+ > l+ vl, (h > z l+ l-, z > l+ l-)Īdd process p p > w- h, w- > l- vl~, (h > z l+ l-, z > l+ l-) Intermediate particles are constrained to be as close to on-shell as possible. Generate p p > z h, z > vl vl~, (h > z l+ l-, z > l+ l-) ![]() For example, Higgs production in association with a Z boson decaying to neutrinos, with the Higgs decaying to four leptons is: For processes with multiple intermediate particles, the decays are separated with commas, and parentheses are used to specify decay chains. The s-channel mediator for a process can be specified explicitly:Īlternatively, a particle can be excluded from all diagrams with a slash:įor generating more complicated processes, the syntax needs to be entered carefully. To see the diagrams for this process enter: This is called the Drell-Yan process, in which a pair of leptons are produced from a Z boson or photon decay. ![]() To generate a collision process, for protons colliding at the LHC, for example: For example, to include b quarks in the jet definition:Įnter q and press enter to exit the interactions file. Multiparticle definitions can be used recursively. You can define your own multiparticles with, for example, to create a multiparticle for the electroweak bosons: Most of the particle names are intuitive, except a, which is a photon.ĭefining multiparticles can save a lot of typing. In the MG5_aMC_v2_2_3 directory, enter the CLI:īy default the standard model is loaded. If the compilation fails at the STDHEP compilation step, the patch can be found at: My test system was missing a GFortran compiler, which I obtained and installed from If this doesn't resolve the issue, try using the exact versions used in this tutorial or ask for help.ĭownload the pythia-pgs package directly from and move it to your main MG directory. You can also check if the error has been resolved on the MG forum at. Make sure you're using a compatible version of ROOT and the environment is set up correctly (see Installing ROOT section below). If there was a problem with the installation of these packages, red text or an error message will be displayed. In the file input/mg5_configuration.txt, change the delphes_path variable on line 122 from Next, we'll install the latest version of Delphes from the developer's site,, rather than the MG site or CLI. Once the installation is complete, you can quit the CLI with: Enter y or n and press enter to continue. ![]() If a newer version of MG is available, you will be asked if you want to update. These packages can be downloaded from the same MadGraph site and installed manually, but it is easier to use the MG Command Line Interface (CLI): The next step is to install the pythia-pgs package. The next instructions are slightly different for Linux vs Mac. Move the tar file to whichever directory you wish the installation to live (I keep a Software directory in my home directory). People could always try out the latest version from bin/mg_aMC, root6 which you can get from CMSSW_8_0_24 for example NOTE: a newer version could be MG5_aMC_v2_3_3, install the Delphes from. ![]() The working combination I found for this tutorial is: MG5_aMC_v2_2_3, Delphes-3.2.0, root-5.34.28 for Linux and root-6.02.08 for Mac. Since there are library dependencies between some of these packages and ROOT, it is usually not possible to have the latest versions of everything. Once you are able to log in, navigate to the Downloads page and click on the link in the left hand column to download As newer versions of these packages are released, the version numbers in this tutorial will need to be updated in the commands. If you have not already set up an account, under the Downloads tab at the top of the page, click needs account, and create an account. If you're new to ROOT, see the section below titled Installing ROOT. Prerequisites: Python v2.6 or newer and ROOT. GREEN: For what the output of a command should look like in your terminal. Here is the color key for line highlighting: To see the physics theory and statistics underlying these packages, check out the lectures at I will cover the basic operations as well as many useful tricks I've learned to save time and customize the event generation, as well as introduce some resources that I've found helpful. These tools are invaluable for phenomenology studies of physics beyond the SM, calculating cross sections, and generating parton level events to pass to other software for full MC generation. This tutorial shows how to generate collision events with as well as how to shower, hadronize, and simulate the response of a detector like CMS with Pythia and Delphes. ![]()
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