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RE: A crash course on particle physics (towards our steemSTEM meetup at CERN) - 5 - The challenges of the searches for new phenomena
Great paper, I enjoyed in particular the graphs showing the fraction of events as function of the collision energy.
I kind of guess what the answer to my question will be, but just want to make sure:
Is there an instrumental parameter that can be tweaked to improve the odds of obtaining interesting collisions ? or, on the other hand, are all these ratios linked to completely spontaneous processes (whatever we do, we can't change the rates of occurence, as for example the decay rate of a given isotope)?
There are so-called triggers that can very quickly decide whether the collision deserve to be recorded. For instance, if there is a muon or an electron with sufficient energy, this is interesting -> recorded. And we have several of these.
You then have several level of triggers (fast ones first, slower ones next). The reason is that the rate is enormous and must be reduced as quickly as possible for something the electronics can handle.
Then, at the level of the analysis, we implement a much stronger selection to isolate a given signal from the background.
Today, we are February 8. I just finished with my last student of the day, and I feel I should be in Geneve tonight enjoying a fresh beer with SteemStem!
I will be thinking about our community tomorrow during your adventure inside the CMS. If you can, please forward to the members present tomorrow my warm regards!
Back to our discussion:
Thank you for the explanation. And what about the unexpected... If the selection is based on triggers... might we not miss something highly unusual (not expected, thus not programmed to trigger a recording)?
Or maybe, there is an algorithm that also filters out all that is expected, leaving only the interesting reactions.
What I mean is that you appear to extract the interesting collisions, instead of filtering out the standard ones. filtering out the standard ones would allow to detect something beyond the standard model if ever it happens. Is this being done? or is it just unrealistic in terms of computational power?
A significant fraction of recorded events is randomly recorded. That allows for the unexpected to happen :)
Aaah, that's good then... sometimes looking too closely at something, one misses what is going on the side. But of course, LHC scientists know that!
Yep, they know. We really want to be ready for anything ^^