By Enio...
This article consists of a report of activities in the context of the participatory research project Citizen science particle physics project on Hive led by 
Task 1: Top-antitop production at the LHC
I went to the directory where I have the MG5_aMC installation and launched the software. Then I entered the command generate p p p > t t~ which, as we can see in the instructions, serves to define the production of a top-antitop pair in proton-proton collisions.
That produced the following output:
I then proceeded to generate the Feynman diagrams with display diagrams, which in turn produced the following output.
It says that several .esp files were generated in the /tmp directory. I took a look and indeed they are there. Below is a kind of thumbnail of the 5 files.
I can't understand these images yet, but according to the instructions we don't need to interpret anything yet.
Task 2: A Fortran code for top-antitop production at the LHC
In order to extract an equation from these diagrams, I have entered the command output fortrancode1. This generates a directory named "fortrancode1" nested in the software directory. Using a new terminal tab I explored the file to verify that the files were generated.
Out of curiosity I opened the dgauss.f file in the /source subfolder.
Task 3: Computing the rate to top-antitop production at the LHC
I went back to MG5aMC to start the process of compiling the Fortran code with launch fortrancode1. This was a bit stressful and in the end I got a compilation error after two attempts. On the first attempt, following the instructions on the interactive menu that appears after using launch, I entered: 1, enter, 4, enter, but failed to edit the line 129 successfully via terminal. The edition process did not behave as expected and I guess it was a problem with Vim. I had to edit using xed, a GUI editor. After that it started running a process for several minutes, but in the end it failed and gave this output:
On my second try, I decided to set Nano as the shell text editor to see how it would behave, but in the process I seem to have mistakenly altered another parameter listed in the interactive menu. The truth is that this new compilation also failed. I guess this has something to do with the fact that I changed the line True = use_syst ! Enable systematics studies by False = use_syst ! Enable systematics studies and the tutorial warned that "the code should just crash because some packages are missing…". The point is, I'm not sure if this won't get me through task 4.
In any case, these processes produced an HTML file as output and was automatically opened by the web browser. I attach this view below:
This closely resembles the results of the tutorial, so it did work correctly, except for the part I mentioned.
Task 4: Checking out whether everything went fine
When I go to the fortrancode1/Events directory, I don't see the run_01_decayed_1 directory in it, but rather run_01.
When I go into them and list their contents, I don't see a tag_1_pythia8_events.hepmc.gz file, but this:
So I don't think I can say that this step is complete :( I hope this information is enough to diagnose the problem. I will be waiting for feedback from
After
However, I couldn't find the Pythia8 output in the log. So I guess it isn't complete yet. I'm pretty sure I enabled Pythia8 by pressing 1 as the instructions say, but I might be wrong, I don't know. What do you think,
After a few attempts and exchanges with
Some References
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