Sunday, July 11, 2010

experimental-theoretical-phenomenological triad UPDATE

CERN has a smaller and often less visible group of theoretical physicists who hand around the same building as the library. They tend to have less students and they move between experimental groups in pursuit of the goals of fulfilling certain predictions that were perhaps made mathematically 30 years or more ago. They are perhaps more reticent than most when it comes to highlighting new discoveries, but I will find out more later this week when I get to spend time with some theoreticians (or at least one of them). I was just looking at the paper that predicted the existence of Higgs in weak and electromagnetic interactions in the Glashow-Salam-Weinberg model written back in the 1977. Energy levels prediced in its production Higgs decay seem to be going on at an energy level way lower than that operating at the LHC at the moment. It will be interesting to try to decipher the differences between the models and realities, and to finesse these differences.

Depending on whom you speak to, some physicists do not see a real difference between a theorist and an experimentalist. Some sees the phenomenologists as a theoretician who is able to speak the language of the experimentalist. For me, I am still trying to decipher the ontological differentials that are going on at this level and will have more to say soon here. Perhaps it is timely to turn back to some philosophical ruminations on this point, though I am not sure if our philosophical knowledge at this point is sufficient to answer the question of knowledge differentials at the micro level, let alone at the macro level. 

Today, I am going to shadow a LHC-CMS shift at some faraway site in France, and should leave here in a few minutes. I may have a lot more to talk about once I am there.

Before any physics can happen, there are too many other considerations to be taken into account. There are the continuous collation of cosmic rays that have nothing to do with the injection of the proton beam.  Then there's parametric control involved with triggers, luminosity,and pixellation (the organization of the thin strips of sillicon tracker and the rays they track). There is also the need for choosing the right data to look at by making cuts on the bunches of information received. Usually no physics data can be acquired until injection studies are performed either over hours or days. From where I am sitting now, no physics is being done yet but other things are happening. At the CMS control room in Versonnex France, we, and all the other experiment control rooms, are keeping an eye on the LHC operations logbook as they key in updates of the injection studies being performed right now. Later, I will upload some pictures of the huge, heavy-industrylike paraphernalia involved in such a delicate task.

I will be meeting two theoreticians towards the end of my two-week stay here, people who are very much involved in the phenomenological developments of high energy physics. Tomorrow there will be more visits to other control rooms of the other experiments as well as perhaps attendance of an analysis meeting, which should be both interesting yet intimidating.

No comments:

Post a Comment