Author Archives: Homer Wolfe

Meteor Shower Zenith Tonight

Tonight is the peak of the Perseid Meteor Shower, which is the roughly annual result of the earth passing through trailing debris from the Comet Swift-Tuttle.  In Hamburg its cloudy as usual, but I’ll be outside for a bit around 2am if it isn’t raining.  Tonight is just the peak, so tomorrow night it might also be worth stepping outside if you don’t live near a lot of light pollution.

Time to pick out some appropriate stargazing music….


Where’d You Get That Supercollider Shirt?

I was skimming an old review of the Coachella Festival today and I couldn’t help but notice that a singer from the band MGMT was wearing a Supercollider shirt on stage. The Superconducting Supercollider was a proposed hadron collider in Texas, and was cancelled after about a quarter of the the tunnels were dug due to US federal budget limitations. It would have been bigger than the LHC, explored higher energies, and been running by now, but so it goes. Construction started in ’91 and terminated in ’93, so that’s probably when the promo shirts were made. I’ve got one too, which I discovered in a box in the server room in at the Pheno Institute in Madison a few years ago. I keep it in a nitrogen vault to preserve it, and mostly only wear it to conferences. I’ve been debating scanning it and getting it reprinted or recreated, just ’cause its so ridiculously awesome.

Social Instability

When you work at an international lab, most of the people you meet and become friends with are only on a 1+1 or 2+1 postdoc, or need to go home every few months for exams, or are only out on a two week or two day assignment. People on permanent assignment also go to at least one conference each year. This does mean you get to meet lots of interesting people from interesting places, but also means your personal interactions also carry an explicit sense of instability. This is also true at any major university, but there’s sort of a communal experience via the academic year. Even though people make friends with students from different years, there are aways people with the same timescale as you. The instability is there, but there are enough people on the same schedule that I found it less isolating and unpredictable.

Here its a bit different, for better or worse. Students and postdocs normally arrive individually, adjust, work and leave on a schedule dictated by their particular institutions. When I first arrived I made a big effort to learn the language fast and make friends off site but, none the less, scientists who aren’t from this city still form the core of my friends. What’s kind of nice is that its like an extended vacation for many people. They come here with few or no local personal attachments or responsibilities, and view their time here both as a career opportunity and simply a great personal experience. Combine this with incessant welcoming parties, going away parties, housewarming parties, and someone-is-back-in-town-for-an-editorial-board-meeting-lets-get-battered parties, and you get a pretty good time. When I was still living at the university we had all these things, but they weren’t so frequent or uniformly spread in time. Then again, scheduling a regular card game or road trip on a weekend when everyone is in town is a bit tricky.

This week is an extreme example, but it gives you an idea. On Sunday, one friend got back in town for after being at her home univeristy for two months. She’ll only be here until the fall, I think. On Monday a friend I haven’t seen in a year came back for just two days to sit in on a meeting. Last night was the probably the last time I’ll play cards with two guys working on the ILC Alignment and Survey project, which recently lost its UK funding. Tonight I go see my a friend who used to be a postdoc for my group, who I haven’t seen since he moved to LHC business a year ago. Its great to see people graduating, getting new and exciting jobs and all, but its a bit sad at the same time. I also notice it when people ask how my thesis writing is going, and where I’m looking at postdocs.

Particle Flow Calorimetry

I took a break today from thesis writing to attend the weekly computing seminar, since it had calorimetry in the title, which should supposedly be one of my skills. The slides aren’t posted yet, but whenever they are you can find them here. Mark Thomson was the speaker, who also has a few papers out on the same subject on the web, this one seems to have the most overlap with the talk.

The idea goes a bit like this: If you want to test new physics at a collider, you need to measure collision products very carefully. Specifically, testing electroweak sector models (all this higgs hubub) requires identifying and differentiating Z and W bosons real well. Single production Z and W’s both decay in to quark-antiquark pairs. We can’t see quarks in detectors directly, but we observe sprays of particles called jets which have basically the same energy and direction, etc. So they want to measure jets real well at the proposed and under-development International Linear Collider (ILC), and the main technique to do this that they are trying to develop is called Particle Flow Calorimetry (PFC).

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The Worst Quark?

So I fly back to the states roughly twice a year, and customs/immigration provide varying levels of irritation/amusement.  I’ve entered O’Hare international about four times, and the setup was a bit different each time I did it.  There’s always passport clearance, then baggage claim, then customs, then sliding doors, and the outside.  One time however, there was a standard blue-uniformed (not TSA) police officer between customs and the sliding door, asking each passenger random questions before they exited.  I overheard him asking the suit in front of me something about the length of her stay and something about a conference, and I step up.  I had been traveling for >12 hours at this point, and all his questions were rapid-fire, which I can’t sufficiently simulate syntactically.  The exchange went thusly:

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Misadventures in Publication

Some of you may recall a readers comment before about publishers manually re-typsetting journal submissions: I now believe this wholeheartedly. You see, the paper that is slowly becoming my thesis got accepted to a respectable journal a few weeks ago, and they sent back some proofs to be double checked before printing.

Some errors could have occurred in electronic reformatting, like all the funding references being dropped. Sure. Then there was ^{+3}_{−1}\% becoming ^{+3}_{−1\%}. Fine. Then there was several “<“s becoming “>”s. Hmmmm. Then there is my personal favorite: “Acknowlegments” [sic].

IceCube Construction Featured on National Geographic Channel

According to my Librarian, The National Geographic Channel will be re-airing a show on man made marvels tomorrow and next Thursday on antarctic construction, with a partial highlight of the IceCube Experiment.  IceCube is a cubic kilometer of arctic ice laden with photomultipliers, and a surface array to detect air showers.   The PMT’s pick up Cherenkov light from fast moving charged particles (mostly muons), which come from cosmic rays and neutrino collisions with the water molecules.  Once completed, you can think of IceCube as being, among other things, a giant cubic telescope that views the universe with neutrinos instead of light.  It also contains an earlier detector called AMANDA, which is shown here as the yellow cylinder.  Photo comes from

NeuroBayes: Sometimes sans Neuro

I went to the weekly computing seminar yesterday, because it was on a statistical data mining tool that is being simultaneously used by physics experiments and marketing firms. The speaker is a physics professor, used to work for the PLUTO Collaboration, DELPHI, and now is variously associated with CDF and CMS. The company, Phi-T, is now totally private, and employs a couple dozen ex-physicists, or physicists, depending on how much of a purist you are. The software is proprietary and closed source, and the speaker was severely vague about what specific tools were actually used, but there is an interface in C++/ROOT/C#/Lisp already made, so its (supposedly) trivial to use, with a discounted academic licence.

So what is it? Basically, you have a vector of measureables, like detector channels, and some target, like say Resonance mass. Or Age, profession, #kids, and your target is “How much will this person cost us in Health Care in the next n years.” You then train the thing on your historic or simulated data, and it generates Bayesian posteriori distributions for new data. This is pretty common in neural computing literature, but this thing seems actually practical.

The only really fascinating thing is the generality of the thing, which was (supposedly) applied with minimal expert consultation on problems like car insurance premiums, to B_s mixing at CDF. Here’s a list of referred journal articles with their stamp. So whats inside? A neural network you say? No! The guy said in most applications they skip the neural net entirely and just use “Other” statistical methods. It’s clear that he was using some kind of input decorrelation like principle component analysis, but he wouldn’t say what specifically. He used a bunch of phrases that were cryptic to me like “zero layer network” to mean something other than a perceptron (I asked), and “zero iteration training” of a network. Maybe these things mean something to yall statters, but nothing to me. Anyways, the output of whatever was a discretized probability histogram that got splined together.

I’m unconvinced that the “default settings” he mentioned could schedule re-stocks for the largest book distributor in Germany AND find the X(3872) resonance, but what do I know? He also said that the companies own stock were controlled by this thing, but that selling it for this purpose is somehow illegal. Anyone know what he was talking about? Here’s a paper on it, by the speaker.

In the end, the talk was a sales-pitch/head-hunt, but if anyone out there needs to solve a highly nonlinear problem and has a cushy grant, go nuts.

Download Hermann Weyl’s 1919 Book For Free

If you speak German, and like science history, you can download Weyl’s 1919 Zeit, Raum, Materie book in PDF for free from The Internet Archive. I wanted a sort of journalistic, “this is how it went down” kind of book, but that doesn’t seem to be the case. There’s some nice first person stuff in the forward, and some nice philisophical musing at the end, but mostly is seems textbook stylie. I just skimmed it a bit, so maybe the gems are buried deeper.

If anyone can find anything on his early attempt at gauge invariant therory of unified electronmagnetism and gravity, I’d be grateful to hear from you.

You can also check out a collection of original papers on Relativity from before 1920, too. These are all translated into english.

I thought that was a joke….

Maybe yall remember when I was writing some conference proceedings last month. I finished them at the last minute (like everything else I do) and mailed in the LaTeX source, the original figures in eps and the resultant dvi/ps/pdf, just like the webpage said. I saw something about instructions for a photograph-ready hardcopy, and assumed it was a courtesy for participants who work in caves* and code on pre-RISC DECs with orange-on-black CRTs. I just got an email from the secretary who is gathering the contributions for the publisher. Everyone has to send in hardcopies. Like, mail in paper. Like, tree-paper. Like, physically. Like, with a stamp. …? I could see it if you submit via Word or some other format that intentionally discourages interoperability, but I used their LaTeX format with no additional (ie modern) packages.

This wasn’t my first rodeo, and I ain’t never had to do this before. I asked an olderwiser about it, and they said “Sometimes they ask you for it. Don’t.” I mean, I will do it, but man, that’s silly.

*no offense to folks at neutrino/DM experiments. Those are mines, not caves.