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Posts Tagged ‘culture’

Particles of the Day

Tuesday, November 20th, 2012
My copy of the 2012 PDG booklet

My copy of the 2012 PDG booklet

Last week, I got my copy of the 2012 Particle Data Group Review of Particle Physics booklet — which, along with its heavy, 1000-page full-length counterpart, we simply call “the PDG.” My very first copy, during my first months at CERN in the summer of 2003, is a vivid memory for me. Here was a book with almost everything you want to know, about every particle ever discovered! It was like the book of dinosaurs I had when I was a kid, and I read it in exactly the same way: flipping to a random page and reading a few facts about, say, the charged kaon.

My new copy of the PDG has inspired me to adapt this fun for non-experts. So each day, I’ll feature a new particle on Twitter; I’m @sethzenz, and the hashtag will be #ParticleOfTheDay. Since starting last week, I’ve featured the B0s meson, the pion, the kaon, the electron, and the Higgs.

How long can I keep this up? That is, how many particles are there? Well, that depends on how you count. The Standard Model has 3 charged leptons, 3 neutrinos, 6 quarks, the photon, and the W, Z, and Higgs bosons. But then there’s all the antiparticles. Dark matter candidates. The graviton. I could even argue for taking 8 days covering all the gluon colors! (Don’t worry, I won’t.) But most of all, there’s all the composite particles — those that are made from a combination of quarks. There are a very large number of those, and there will always be more to find too, because you can always add more energy to the same combination of quarks.

The point isn’t to be systematic. I might go back and be more specific. I might repeat. What I really want to do is find a particle each day that’s in the news or I can say something interesting about.

Flipping at random through a book of particles turns out not to be the best way to learn particle physics; ultimately, I needed to learn the principles by which those particles are organized. But it is an interesting way to tell the story of particle physics: its history and how it’s done today. After all, the particles do come out of accelerators in a random jumble; it’s our job to organize them.

Have an idea for the Particle of the Day, and what to say about it? Let me know!


Are the Higgs Rumors True?

Monday, October 22nd, 2012

What Higgs rumors, you may ask? Well, there aren’t any that I know of, yet. But there might be soon…

There might be rumors soon because we are about to do another round of updates, for the 2012 Hadron Collider Physics Symposium (HCP). There aren’t any yet because our results (at least on CMS) are still “blinded,” which means that we haven’t actually looked at the “places” in the data where we see signs of our new boson. What we’re doing instead is looking at simulated data to see how much our results might improve when we add in the collisions we’ve recorded since ICHEP. We’re also putting in a few new analysis techniques, and checking them in the same way. And of course we are looking at data in other “places,” and we’re comparing it to simulations to make sure they’re doing a good job.

There will be several weeks between the moment we “unblind” — that is, look for the first time at what our signal looks like with the new data — and when results are shown at HCP. This is just as things were at ICHEP, and during those few weeks there were a lot of rumors around. It’s not possible to confirm or deny rumors when you know the status of ongoing work but haven’t yet agreed with your colleagues that it’s finished and ready to talk about publicly. So this time, I’m going to get in some general comments about rumors before I know anything at all about actual results. These comments will apply just as well to future updates.

What are we doing during the gap between unblinding and the conference? We’re checking our results, and putting them in a final presentable form. This is already compressed into a very short, hectic time, as I’ve written about before.

Are the rumors true? They are definitely not our official results, but they might turn out to be close. Or they might not. Specifically, the possibilities are:

  • A rumor is pretty much right. It’s no secret that particle physicists are bad at keeping secrets, and we really don’t want to be good at it. If one in 3,000 physicists decides to tell the Internet what our first-pass internal results look like, we can’t really stop them. Of course they’re breaking the rules, and we wish they wouldn’t, because it’s a collaborative effort and we’d prefer to agree together that we’re finished before announcing our results — because we want to make sure we did everything as well as we can. But still, our first-pass results are usually pretty close to final.
  • A rumor isn’t quite right. This could happen if we do find small mistakes or make refinements in the last few weeks of analyzing the data. This changes the answer by a bit, so the rumor is out of date. You could also make up a “not-quite-right” rumor just by making an educated guess based on our last results and how much new data we’ve taken!
  • A rumor is just plain wrong. Nobody says rumors have to be based on anything. Or they could be based on a misunderstanding of far-from-complete internal results.

We physicists working on this stuff don’t find it easy to wait for the answers either, and as Jon Butterworth has pointed out, rumors of other experiments’ results are actually dangerous for our work! For everybody else who’s tempted to indulge in rumors, just remember: you might be getting part of the picture early, or you might not. The only way to be sure is to wait for the next real update.


What Goes on My Research Page?

Thursday, August 30th, 2012

It is time, it seems, for me to put up my first real departmental research page. This is a place to put up a picture, describe my research interests, and maybe link to some papers. It shouldn’t really be too difficult to write something up, as I have seem to have acquired a disturbing amount of practice in rambling about my research and putting up web pages about myself. But looking at others’ research pages has left me with a nagging question: what, really, are my research interests?

“CMS and ATLAS are two of a kind: they’re both looking for whatever new particles they can find.” — Kate McAlpine, Large Hadron Rap

In most fields, I would talk about a very specific set of problems I was interested in, and say what sort of experiments I was doing to figure things out. But the big detectors at the LHC try to look for everything, and I work on them because I’m interested in finding anything new that’s there. Am I especially interested in electroweak symmetry breaking because I work on the Higgs boson? Am I a precision tracking enthusiast because I’ve worked on pixel detectors? Well, yes, to some degree both those things are true — but the fundamental motivation for my research is to contribute to the overall program of understanding what the universe is made of, by whatever means my skills and the available opportunities allow.

Still, I suppose I had better be a bit more specific. Anyone have any suggestions?


DPF 2011, tweet tweet!

Friday, August 5th, 2011

I know, I know, everyone has been focusing on the EPS and Lepton-Photon conferences (not to mention repeatedly putting in hyperlinks to their Web sites), but let’s not forget that the 2011 Meeting of the Division of Particles and Fields of the American Physical Society (DPF 2011, for short) starts this coming Tuesday. This will be the largest conference exclusively focused on particle physics in the United States this year, and it’s organized by the nation’s grass-roots membership organization of physicists, the APS. There are currently more than 450 people registered, so a large slice of the US particle-physics community will be there. This will be the fourth time that I’ve been to a DPF meeting, and I really do enjoy them — they are large enough to cover a broad range of topics, yet still small enough that you don’t get lost in the crowd.

For the first time ever, I find myself giving two presentations at the same conference — one on behalf of the CMS Collaboration (on the status of our distributed computing operation) and one on behalf of the D0 Collaboration at the Tevatron (on measurements of spin correlations in top-antitop production). On top of that, I’m also co-organizing a lunchtime panel discussion on “physics and the modern media.” What you are reading right now is a form of modern media, of course. We’re going to be talking with science journalists, communicators and bloggers about where communication about science is going…and what these sorts of people think of each other!

Since we’re going to talk about modern media, we figured that we should jump in with both feet, and that means Twitter. I must admit that I haven’t done much Twitter (although I do now have an account), but it seems to be all the rage. So, we’re encouraging Twitter users who will be attending the conference, and those who aren’t but want to keep up with what’s going on, to tweet away using the hash tag #DPF2011. If you are interested in the modern-media panel, feel free to tweet to us on Tuesday at 12:30 PM Eastern time; we’ll be keeping an eye on the feed and relaying interesting comments and questions to the panel.

More next week from fabulous Providence, Rhode Island!


Sorry, terrible title, as it references an ancient slogan for a now-defunct car brand. But what do you want — it’s the Friday before a holiday weekend!

Today marked the end of the June CMS week, one of three full-on collaboration meetings that the experiment holds each year. Honestly, I find these things overwhelming. It’s an opportunity to get a full view of everything that is going on within the collaboration. This spans detector operations, the trigger system, computing, plans for future detector upgrades, and all the data analysis that is taking place. Of course there is some talk about the challenges that we face — increasing luminosity, more complex event environments, the pressure to get results out promptly, the issues of keeping such a large collaboration organized and efficient. But we also get to see some of the best work that is being done by our collaborators. Some of the data analyses out there are really creative and clever, and you have to tip your hat to the people who are doing the work.

And I sit there thinking: Why am I not working on this myself? Actually, why didn’t I even know before that the work is going on? There are huge swaths of the experiment that I’m barely following, even though they are important. It’s somewhat demoralizing to have trouble keeping up with all the activity that is out there.

I console myself by saying that this is really an issue of scale. Consider the CLEO experiment at Cornell, where I did my PhD thesis about fifteen years ago. At the time it wasn’t the largest collaboration out there, perhaps half the size of one of the Tevatron collider experiments, but it was still substantial, with about 250 people on the author list. I could identify almost everyone in the collaboration on sight, I was reading pretty much every paper that went out, and I had a pretty good handle on what the hot topics were throughout the experiment.

So I need to keep some perspective and remember that these are different times and the LHC experiments are about a factor of ten larger than my thesis experiment. A single LHC experiment is now on the scale of 1500 PhD scientists, which surely puts it on the scale of a major research university. And who would expect to know everything that’s going on inside a research university?

Looking on the bright side, a group of scientists this large, all focused on the same goal, can really do amazing things. One of the amazing things is the ability to collaborate on these scales of both size and distance. But better still will be what we think and hope is coming — a revision of our understanding of how the universe works. It does take this many people to pull it off, and I shouldn’t be embarrassed by the fact that I don’t know what everyone is actually doing.


Perks of the job

Friday, September 17th, 2010

Life as a high energy physicist is not without its perks.  I recently got back from my latest trip to CERN for the EMCal test beam.  I spent about a week on the midnight to 8 AM shift and then stayed a week to work with some of my collaborators in ALICE.  The hours are long and the work is hard but the company is good and there are many perks.

I’m an avid hiker so I took a day off to go hiking in the Juras.  My friend Daniel organized it and we ended up with a group of two physicists from ALICE, one from CMS, one from ATLAS, and one from a university in France.  We had one American, one Brit, one Spaniard, and two Mexicans.  A multicultural group in many ways.  Here you can see the view from the Juras:

Somewhere down there is CMS.  It was a nice hike but next time I’ll pack my good compass and get my own trail map.  We had some unintentional adventures.

After my trip to CERN I went to a conference in Sicily – which means I had to work on a talk while I was at CERN.  Of course Sicily is beautiful:

(This is the view from Taormina during the excursion.)

Then I packed up and left, first to Geneva and then back to the US.  Five flights and four countries in two days.  My luggage made it through Paris to Atlanta but then decided to take a vacation in Atlanta without me.  I’m now looking at a grueling travel schedule in the next four months.  Plans have changed and our detector, the electromagnetic calorimeter, is going in during the Christmas shutdown.  This is great news but it also defines my holiday schedule – November and part of January at CERN.  On top of that I have a few meetings and some personal travel.  I’ll be lucky if I manage to be home for two weeks in December.  However, I did not get much sympathy from my father the other day when I was complaining about how I might have to get extra pages in my passport because I’m running out of space.  Go figure.


The cost of a PhD

Thursday, June 3rd, 2010

It costs a lot of money to produce a PhD scientist.  A rough estimate, based on my education:

  • Primary and Secondary education:  For simplification, let’s say I spent all of my k-12 years in Colorado.  Colorado ranks roughly 42nd in per-pupil spending, but it still costs $8,600/pupil/year for k-12 education.  Therefore, my high school diploma cost roughly $112,000.
  • Bachelor’s degree:  I went to Colorado State University for my undergraduate degree – a large state university.  Colorado State was a great bargain and when I started there, in-state tuition was roughly $2000/year.   Most of this was covered by scholarships, so was actually paid by some branch of government.  However, CSU spent roughly $20,000/student on undergraduates, with the difference made up from the general fund.  I spent five years in undergrad, so just the tuition for my degree was worth roughly $100,000.  Fort Collins, CO was pretty cheap to live and I was an overwhelming cheapskate.  My cost of living averaged about $10,000/year, adding another roughly $50,000.  Additionally, I participated in four summer undergraduate research programs.  One program was at CSU and my participation (salary and other expenses, excluding the salaries of my supervisors) cost roughly $4000.  One program was at UNC Chapel Hill and I got paid $3,000 plus room and board and transportation to Chapel Hill, so this cost roughly $5,000.  One program was in the Netherlands for five months and this probably cost roughly $10,000.  One program was in Switzerland for two and a half months and this probably cost roughly $10,000.  So the cost of my supplementary training as an undergraduate was roughly $29,000.  Therefore the total cost of my undergraduate degree was roughly $179,000.
  • Doctorate:  The average time in graduate school in physics in the United States is six years.  I spent six years and two months in grad school.  Grad students in physics don’t pay for their tuition, but tuition is paid to the university by the grant.  At Yale, my tuition was about $20,000/year.  In addition, my stipend, my supplementary salary from teaching, the cost of my health insurance, and overhead added up to at least $40,000/year.  This adds up to at least $360,000.  On top of that, I took trips to conferences and to take shifts.  My travel for my research definitely pushed the cost of my graduate degree to at least $400,000.

Therefore my PhD cost roughly $691,000.  This is not a precise calculation and one could certainly quibble with details.  I’m sure that people with more knowledge about grants would say I’m actually underestimating a lot of costs.  A PhD at Yale is probably more expensive than at other schools, but it still easily costs well over half a million dollars to produce a PhD.  That’s a huge investment for society to make in a person – and I’m very grateful.

I benefited significantly from scholarships and grants.  Other than paying taxes like everyone else, my family and I probably paid less than 5% of that cost.  Some costs were picked up by private organizations through grants, awards, and scholarships, but most of it was paid for by some branch of the government.  My teaching, tutoring, and research does have economic value – I don’t see myself as a leech on society – but I do owe my education and the opportunities I’ve had to the kindness of taxpayers.  If we did not live in a society that at least strives to create equal opportunities for all, I would not be where I am.  Because of the debt I owe society, I feel it is my responsibility to give back – to use my education to explain what I do to the public and to help inspire and train the next generation.

At the same time, society benefits from having highly educated people.  I am doing basic research that will most likely not lead to a marketable product in my lifetime.  But basic research is crucial to future economic developments.  Research in high energy particle and nuclear physics has led to cheaper and better particle detectors which can be used for medical technologies.  CERN played a crucial role in the development of the internet – certainly more than Al Gore – and it still does.  All of the experiments at the LHC use a computing infrastructure called the grid and developing the grid took substantial improvements in networking and distributed computing.  Studying the Quark Gluon Plasma will not directly feed the hungry or cure cancer, but we move the boundary of what is possible and this benefits humanity.


Hi, Seth here.  It’s been a while since I’ve written about my work, mostly because my work lately has been time-consuming and a bit complicated to write about.  Nevertheless, I’m going to take a stab at it.  About two weeks ago now, I gave a talk at the APS conference (which Regina gave a talk at also).  Preparing for the talk was a more challenging process than I had expected; I knew what I wanted to say, but what I showed also had to fit within the goals of ATLAS as a whole.

I had originally written in my abstract for the talk that I was going to describe the method for my track jet measurement, but I had always hoped that I would be able to show some initial collision data in order to demonstrate things were going well.  And indeed, I had that data, and things looked pretty good to me.  But of course, when any ATLAS collaboration member shows the results of our work outside the experiment, we are relying on years of hard work by thousands of people, and we are speaking for everyone in the experiment.  That means that my colleagues had a say, as they should, in what I would show in my talk and how I would show it.

Showing my plans and simulated results wasn’t a big deal, in part because ATLAS has special rules for “work-in-progress” by students. But there were definitely questions and discussions on whether we ought to show plots based on real collision data.  Let me summarize a few of the potential issues:

  1. My talk was very early.  Except for an initial flurry of quick plots right when we got first data, ATLAS is showing its next round of more polished plots of detector performance in March. Did it make sense to release some of that work ahead of schedule?
  2. Was there time to make sure my results were correct?
  3. My own plots rely heavily on the work done for our experiment’s first paper, the “minimum bias” analysis.  (It shows the distributions of charged particles in our detector, including as many events as possible — hence, “minimum bias.”)  That paper isn’t out yet (but the one from CMS is).  Did it make sense to show work that depended on other, not-yet-published work that might change?

These are important questions.  Some of my collaborators thought the answer was yes and some didn’t, and the resulting discussions took time and energy.  In the end, I did get to show some of what I wanted, but not all of it.  I can’t say I was completely happy about that, but I did end up getting to show some of my work only a few months after we collected data, and that’s cool.

I fully agree with the need for ATLAS to have a set of procedures to make sure that our work is presented appropriately and that it’s correct.  A big experiment relies on consensus, so obviously I won’t always be completely satisfied with the outcome.  As as an experiment, we’re also still in the process of figuring how to apply those procedures now that we have real data to discuss.  It may not have been easy, but reaching agreement on my talk was an educational experience.

The plots from my APS talk aren’t posted anywhere, but you’ll get to see improved versions of them soon —  I’ll let you know.


Learning French

Tuesday, November 17th, 2009

From a grad student in particle physics, these are my recommendations for learning a bit of French.

Before You Know It

Screen shot 2009-11-17 at 11.22.21 AM

I’ve tried out several language programs, including really expensive ones like Rosetta Stone.  Out of them all, this flash-card program has been my favorite. With each card there is a picture and sound recording of someone pronouncing the word or phrase. It quizzes you on cards and repeats ones you get wrong.

The free version lets you download sets made by other people from the main site, and also comes with a handful of card sets.  The paid version gives you a few thousand cards and lets you make & record your own flash cards and upload them to the site for others. It cost me about $50.

(I should find a native speaker and create a useful set of cards for physicists who come to CERN…)


Les Nombrils


As a comic book about girls in high school, I do feel a little weird buying these, but they’re so funny and filled with a lot of French I never learned in textbooks or class.

This has been my favorite source to learn modern slang or just informal phrases and such.  Words I’ve learned include: mec for “guy”, biche for “girl,” hyper-top for “cool” (I think?), and caleçon for “boxers (shorts).”  A mini-jupe is a mini-skirt.

So if you’d like to learn informal French related to relationships, clothing, teenage life, or the like, check out these comic books.

Alright, I’ll admit it: I own the whole series.


Coffee Break French

Screen shot 2009-11-17 at 12.17.26 PMI download these podcasts and listen to these when I’m driving. They’re slow and clear and leave space for you to try pronouncing words and phrases yourself.  With this you can learn about simple things as well as more complicated topics like tense and grammar.

These are definitely more useful when you are alone and can talk out loud without looking weird.



Using Facebook for Physics

Wednesday, August 19th, 2009

Often in my day-to-day work I encounter some little problem in software or mathematics that I figure somebody ought to know the answer to.  In my years as a graduate student, I’ve learned that the quickest way to solve these problems, if a cursory search of the internet and a few standard references doesn’t help, is to actually go around the office and ask the people I know who work around me.  Sometimes they don’t happen to know either — but I can’t shake the nagging feeling that somebody I know knows how to solve the problem.  My solution to this, on a few recent occasions, has been to turn to Facebook.

Thus last Thursday afternoon, my Facebook status was:

Seth Zenz needs a statistician. Or anyone else who knows how to find the error on a correlation coefficient.

Within a couple hours, two of my friends, one a physicist and one a friend from college, had replied with the correct answer, which turned out to be explained on Wikipedia — which pointed, in turn, back to the original statistics paper from 1921 that answered the question.   So Facebook is good for more than just keeping up with my friends; it also expands the size of “the office” I can go around to ask questions in!