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Is the LHC Doing Physics? March 24, 2008

Posted by gordonwatts in LHC, physics life, Tenure, university.

One one of my lasts posts about computers and HEP, Kevin left a comment.

It would appear to me that the LHC has been for many years “methods development,” yet I’m assuming a couple people already have tenure on it and more than a couple Ph Ds have been awarded for developing the technology.

As far as I know, in the USA, no institutions will give a Ph.D. for an experimentalist if they have not touched data. As far as I know, no one has managed to get an experimental LHC Ph.D. in the USA by just running Monte Carlo or working on a bit of the detector. Now, parts of the LHC have taken data — i.e. the test beam.

The point of the test beam is exactly as it sounds – we put portions of the detector in the test beam to test them out. We fire known particles at known energies into bits of the detector and make sure they react (and readout) as we expect them. If they don’t, we adjust the physics models we use to simulate them or perhaps find something wrong with the detectors and fix them. It is not common to get a Ph.D. in the USA on test beam data, but it has happened. For example, D0’s initial startup (Run I) was so delayed I think a few people did this and then remained on D0 as post-docs to get their hands on real data.

Europe is different – there you can get a Ph.D. on Monte Carlo studies or on building a detector. As far as I know, it isn’t viewed as any different than getting a Ph.D. on data.

But, if you are in the USA, what do you do? This is exactly why most HEP groups maintain a foot in more than one pie. For example, I do a lot of work on ATLAS now – but I also do a lot of work on D0. D0 is a running experiment and produces real results. My tenure decision was on D0. I could have started on ATLAS when I arrived at UW 8 years ago – there was plenty of work to do – but it was correctly seen as suicide. Instead I worked on D0. I only just now have graduate students working on the LHC. I bet if you looked at the number of US graduate students on the LHC it was rather small and is now rapidly increasing. And that is because we are finally in the time frame that these students can get a Ph.D. on LHC data.

Finally, I have heard of programs that offer Ph.D. in detector physics and accelerator physics – which is very different from the work I do. I know less about them than I should, however.

However, Kevin correctly points out, once you are past the tenure bar you can just do what you want. Want to put all your marbles in the LHC basket? Go for it – no problem! Directly addressing the implied question in Kevin’s comment – presumably the person on the LHC who is making these criticisms had to go through the tenure process. And hopefully they are applying the same standards that were applied to them. Sometimes it is hard – I went through the qualifying exam as a student. Hated it, and it wasn’t clear that it offered any net gain for me or my fellow students. I passed, and now, about 15 years later, I sometimes catch myself thinking “it wasn’t that bad…” Some people carry that to an extreme. In the tenure case this is exactly why it is necessary to consult with other people in the department to understand if this is something unique criticism held by one person or is generally shared criticism.

Final installment of this 3-part series next. 🙂

UPDATE: Changed the tone of MC physics paragraph above.



1. Anonymous - March 25, 2008

“a foot in more than one pie”?

not bringing you to dinner … 😉 I usually hear
“a foot in more than one camp” or “a finger in more than one pie”

2. gordonwatts - March 25, 2008

If the worst I do is mix my metaphors… 😉

3. Index Guy - March 26, 2008

I really like “a foot in more than one pie”. It sounds as if the whole situation creates some sort of sticky mess. I will introduce that phrase into my normal vocabulary 🙂 .

Today there was a thesis defense at Stony Brook titled “Topics in the measurement of the electrons with the ATLAS detector at the LHC”. Sadly I did not attend it, so I do not know what was it about, but this is the HEP experimental group. Is this that test data you mentioned?

4. gordonwatts - April 7, 2008

Yes — that is what I meant — I suspect that was test data. I don’t know the thesis, however.

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