Life as a Physicist

Ok, this wasn’t April 1st, rather April 4th. What is worse is CMS saw him first. Darn!

That picture is of the ATLAS detector and Peter Higgs, the fellow whose last name is attached to the Higgs particle - the particle that all of us are after.

See? ATLAS saw him!

Coincidentally an email conversation broke out on a D0 mailing list around the time of this picture discussing the origins of the Higgs mechanism. It was sparked by this yahoo news article. The title is “‘God particle’ expected to be found soon.” Hmmm. Expected to be found? Not sure we are that sure… At any rate.

The email conversation was interesting because because it pointed out that in science often more than one person has the same idea at the same time. Discovery is partly having all the bits in place to build the discovery on. Once all the bits are in place then several people can make the leap.

I’m not familiar with this bit of history, besides Peter Higgs, there was also Robert Brout, Francois Englert, and Tom Kibble in Europe. There are two in America too - Gerald Guralnik and C.R. Hagen. I note that on the Englert page what we normally call the Higgs mechanism is called the Brout-Englert-Higgs mechanism. On the Kibble page it notes that he is credited with the co-discovery of the Higgs with Guralnik and Hagen, the beauty of wikipedia! [they are all basically right, I believe]. Oh — hey — and the UR home page has something up about Hagen as well.

I went to the University of Rochester for my graduate work and my quantum mechanics class was taught by Hagen. At the time I didn’t fully appreciate the work he had done.

BaBar closed down the other day. Well, the long running PEP-II collider shut down, and BaBar depended on it for its collisions. The shutdown came a bit earlier than planed due to the science budget cuts.

BaBar has had a long career. If you are curious about its legacy just check out the 528 or so published papers that can be found on SPIRES. It will be missed!

I really didn’t want to say something about this article. Actually, at first I wondered if it was just an excuse to show a truly awesome picture I wasn’t going to write anything. But then it started showing up on tech blogs, it rose to near the top of the New York Time’s most emailed articles. And non-physics friends of mine started asking what I thought about it. And then I saw some of the comments left on the article at the Herald Tribune’s version of the article (read them - it is worth it). I agree with Peter Woit: “it’s unclear why the story deserves any attention” However, I can hold out only so long.

Here is what I think: this article has the legs for reasons similar to why ID and Creationists are able to push the “evolution is only a theory” so effectively.

If you don’t have time to read the article: Wagner (ex physics researcher, lives in Hawaii) and Sancho (author, researcher on time theory (!?), lives somewhere in Spain) are suing Fermilab, the Department of Energy, and CERN to prevent the LHC from being turned on. Their’s is a doomsday worry: a small black hole or something similar will be created in the center of one of the detectors and will quickly expand to eat up the whole universe. Including us. I actually think that I’ve seen Wagner. One day, when I was a graduate student at Fermilab, I remember seeing a collection of people protesting outside the Batavia gate. I didn’t stop, but some friends did. It was someone from Hawaii who was worried we were going to end the universe. I don’t remember the name, but I suspect it was Wagner.

Now, in the evolution and creationism debate we scientist types call evolution a theory. In science it doesn’t get much more iron clad than that - pretty much the top of the heap. Note that we very carefully do not call it a fact. The reason is that science is always looking to improve the answers. We may have a model that fits all of our observations - but that isn’t to say that we’ve not missed something thus will need to extend the model or theory at a later time to account for new observations. Scientists are very careful about declaring the limits of their knowledge, and are very reluctant to go out on a limb and make a statement for which they do not have supporting evidence. That is part of the reason why we don’t call evolution a fact.

Now, lets go back to the article. There are lots of papers talking about mini-black holes and their possible production at the LHC. So far no one has seen any evidence of a black hole generated at any of the operating accelerators. But can you get any scientist to declare: “Absolutely, under no circumstances, ever will there be a black hold like this produced.”? I doubt it. If you asked a particle physicsts if they were worried about it - I don’t know of any that would be. Most would love to be at CERN, in fact, when the LHC starts up. I’d love to be there, but I may be teaching instead.

There is another aspect in this - risk evaluation. For example, it is much more dangerous to drive in your car than fly in an airplane. That is the raw science (statistics, whatever) of it. Yet we fear flying. When it comes to something like this how do you evaluate the risk? There is no way a non-scientist can do it themselves. The more science literacy there is the better people will understand the language that scientists use, but… And there is no way you would want to limit scientific endeavors and research to the list of topics that the non-scientist can easily understand! Ahhh… outreach!

Obligatory joke: fear not; us particle physicists will be first to pay if we’re wrong.

But you have to admit — that is one amazing picture of CMS! These large detectors are stunning. I think someone should gather up the copyrights for some of these pictures and make a lulu.com book or something like that.

Sean Caroll, one of the famous bloggers behind the Cosmic Variance blog, is giving the colloquia in my department today at the University of Washington. Unfortunately, I’m over here in Marseille, so I’ll miss the talk. Too bad, because he always gives a great talk! Good luck, Sean!

I missed another great talk by the deputy spokes person of ATLAS on Monday, Fabiola Gianotti, which from reports sounds like it was fantastic. I’ll have to get those slides.

As I write this the exchange rate is about $1.54 US to one euro. This will probably come out the middle of next week - no telling what it will be then.

When I moved over here on July 1 the dollar was $1.35 US (see Yahoo! Finance).

Even though France is helping out by paying me a per-diem over here, it is paid in constant dollars. Darn.

Our graduate students and post-docs over here are in the same boat. They are also paid in constant dollars. It is worse for them, of course, as they are paid less than I am and so have less of a cushion to fall back on (I don’t even want to talk about what has happened to my savings account during the stay over here!).

Indeed, we just had to raise the student’s battle pay in order to account for the exchange rate difference. Where does this money come from? Our grant, of course. To supplement the grant so that it can accommodate these increases we are asking for extra cash, of course, but everyone doing physics over in Europe is in the same boat and there just isn’t much extra money in the various funding agencies coffers after the last budget battle.

I don’t see the dollar coming down soon. I keep hoping it will plateau. This latest turn-around is, I think, only temporary. But it is definitely cutting into our ability to send people over to Europe, and we do science with people - less people, less science. It started with a small fraction of bad loans, which is slowly claiming more and more people - and now spreading out from the housing sector to the financial sector and… to the science sector. If there is such a sector!

BTW - when the insurance adjuster dropped by we talked a bit about the financial crisis in the US. He said it was a scandal: “Why haven’t you guys caught the people responsible?”

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

OK, this post forces me to ask this question: can you estimate the amount of time you spend on “science” questions versus methods development, programming or other things? After reading your blog (and enjoying it of course) for over two years now, I feel you have discussed a lot of issues in programming, ROOT, C++ vs other languages, computers and other things that are tools to do science but which are not themselves science (or at least not physics).

I am fundamentally lazy. Other bloggers — like Tomasso — are not. I’m afraid I do not spend much time on these blog posting (spelling errors!? Me!? Never!). As a result, I tend to write about things I can clack off without having to do any reading or extra research. This usually boils down to physics I’m working on or support work I’m working on, hobbies, or my social/family life. I don’t understand how Tomasso has the time to read and digest all those papers. I suppose once you get going you can do it more and more and more quickly, but I have not been willing to take the time.

The physics, however, suffers. For example, I’m working in the Higgs group at D0 - well, mostly my post-doc and my graduate student are this year - but I can’t really talk about some of the very cool stuff that is happening there. That is a sure way to get hit on the head by the collaboration. In ATLAS I’m also doing some stuff I would love to talk about - but ATLAS has an official blogging policy (i.e. don’t, unless the result or thing is public).

Now, part of the reason I got into HEP is I like that it lives at the corners of physics, software, and hardware. Since D0 has matured, I’ve not been doing very much hardware. The software side of things I’d always done as a hobby. I have always been a big fan of software and have made some fairly flexible and sophisticated frameworks for use in physics analysis. Since that, and watching people who are not me try to understand and read my code, I’ve come to believe C++ just isn’t all that great as a productive programing tool. Now here is the thing: no one cares about software! The byproduct of that is I can talk about software freely on this blog, as I work on it. Take ROOT for example, I recall trying to get a new plot out for single top. With that plot we were able to understand that the way we were doing our b-tagging in our background sample was correct. But in order to make that plot I had to fight through a ROOT bug. Guess what I can write about in the blog?

So, now a direct answer to your question. I’m on sabbatical this year. I would say it was about 50-50 for me. When I’m teaching a course I understand, it is probably 40% physics, 30% software, and 30% teaching. When I’m teaching a class I’ve never taught before it will probably by 10% physics, 10% software, and 80% teaching (ask me in November).

Thanks for the question/comment Kevin. I hope I’ve answered it!

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.

I’ve long been a fan pictures of things physics. Physics generates some truly spectacular images and is one way to make it more accessible! A few years ago as chair of the awards committee I ran a small photograph contest for members of the department. That was fun. But department level efforts like this are small time.

The APS is currently collecting photos of research to put on their home page. I wish they would publish a picture book of these things - and expand the selection of pictures they currently have up (a history).

BTW, if you want to see a large archive of particle physics pictures you should check out the Fermilab archive of pictures (click on the 5 blocks at the top to select the type of pictures).

I gave the colloquium at SFU last Friday. It is always fun to visit there - I’ve known Dugan O’Neil up there for many years now. I was originally signed up to get a talk on recent results from DZERO, but I just didn’t see how I could cover the whole of the DZERO physics program and do it to an audience that was only fractionally particle physicists. So I narrowed it down. Waaaay down. To just the Higgs search, which I’m now working on at the Tevatron. And I tried to pull back the covers and talk in some detail about b-tagging efficiency determination and how we are going after improving the jet energy scale.

The talk was a solid “meh” in my opinion (pdf, pptx - copy if you want, but make sure). I did several things wrong. First, it was too long. That is normal for me. Next, I tried to talk about the connection between long and short scale experiments: the “joining” of astrophysics and accelerator based particle physics. While this is neat, and something everyone should be thinking about (I think) the discussion didn’t really have any bearing on the rest of my talk: I should have cut it out to free up time. Second, my description and motivation of EW symmetry breaking was not well motivated. I need to work to improve that.

Last, I was trying to figure out how to tie the detailed discussion into the topic of the Higgs search in general (jet energy and b-tagging). I didn’t motivate it well enough. I really needed some slides that would firmly connect the high-level pedagogical part of the talk with the details. I find the details fascinating and the problems we are trying to solve very hard (one of the reasons I like them), so I don’t want to drop that part of the talk. But it definitely needs to be modified and better connected so it isn’t quite so seminar-ish.

I think it took me about a week to prepare these slides (a 50 minute talk!). One of the nice things about putting a talk like this together is that it forces one to take a step back. I’ve had a few good ideas - now, lets see if I have time to get after them. First, I need to dig myself out of all these accumulated emails and small things that await my attention! It is nice to have the talk over, however!

Hey - it is that day that is the reputed bane of all scientists — because, of course, we all stay inside and work all day and have no social life!

Ha! If only they knew!

Guess what I’m doing today? Hmmm. Staying inside and working.

I’m giving a colloquium at SFU tomorrow and it isn’t “quite” done yet. It keeps getting to the “first draft” stage, and then I think “no, that slide isn’t right, lets expand it a bit” and one slide becomes 5! At one point I was up to 85 slides for a 50 minute talk. I’m down to 69 now…