RE: Citizen science on Hive - Deciphering top quark production at CERN’s Large Hadron Collider
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This set of tasks was really enjoyable for me. 😃 I was able to reproduce the plots and did some trial and error for the homework with regards to identifying what parameters of the histogram I should use to get a reasonable result, although, I am not even sure what is the right answer I'm looking for. 😅
I do have some questions as I was starting to write my progress report..
In particle physics, the term event is referred as the fundamental interaction of the subatomic particles as defined in this Wikipedia article. In this project, we are working on the top-antitop pair, are the events we are concerned of limited only to the top-antitop pair interaction or it also extends to the interaction of the subatomic particles produced from their decay?
This particular simulation has a number of events N = 10,000. From this histogram (left) normalized to results from the full run 2 of LHC, the number of particles produced are of magnitude x10^6 which is ~1,000,000. And in the histogram on the right, is it correct to say that it shows the number of events that produced N number (or the multiplicity) of leptons ? To follow on this, the y-axis on the histogram is also in the magnitude of x10^6, are the number of events with leptons in the final state ~1,000,000?
Thank you in advance for answering my questions, this will surely help me as I continue working on my progress report. :)
I am glad to read that you enjoyed the exercises. It is important to keep everything as funny as possible (otherwise in my opinion we lose a lot!). I will tried to clarify and provide answers to your questions. Feel free to come back to me if needed.
In our jargon, what is traditionally called an event is a specific collision, which could be a real one or a simulated one. We simulated 10,000 LHC collisions giving rise to top-antitop production. This means we have 10,000 simulated events.
The reason is that we simulated 10,000 events, that corresponds to millions of events according to the characteristic of the machine (the full LHC operation run 2). This is why there is a difference in normalisation. In other words, one simulated event then counts for many events. This allows to get the global normalisation correctly (a 500 pb cross section times the 140/fb luminosity = 70,000,000 events).
Does it clarify?
Yes, this answers my questions clearly. Thank you! :)
Great! Good luck with your upcoming report! ^^