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Seth Zenz | Imperial College London | UK

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Will Self’s CERN

Friday, January 16th, 2015

“It doesn’t look to me like the rose window of Notre Dame. It looks like a filthy big machine down a hole.” — Will Self

Like any documentary, biography, or other educational program on the radio, Will Self’s five-part radio program Self Orbits CERN is partially a work of fiction. It is based, to be sure, on a real walk through the French countryside along the route of the Large Hadron Collider, on the quest for a promised “sense of wonder”. And it is based on real tours at CERN and real conversations. But editorial and narrative choices have to be made in producing a radio program, and in that sense it is exactly the story that Will Self wants to tell. He is, after all, a storyteller.

It is a story of a vast scientific bureaucracy that promises “to steal fire from the gods” through an over-polished public relations team, with day-to-day work done by narrow, technically-minded savants who dodge the big philosophical questions suggested by their work. It is a story of big ugly new machines whose function is incomprehensible. It is the story of a walk through thunderstorms and countryside punctuated by awkward meetings with a cast of characters who are always asked the same questions, and apparently never give a satisfactory answer.

Self’s CERN is not the CERN I recognize, but I can recognize the elements of his visit and how he might have put them together that way. Yes, CERN has secretariats and human resources and procurement, all the boring things that any big employer that builds on a vast scale has to have. And yes, many people working at CERN are specialists in the technical problems that define their jobs. Some of us are interested in the wider philosophical questions implied by trying to understand what the universe is made of and how it works, but some of us are simply really excited about the challenges of a tiny part of the overall project.

“I think you understand more than you let on.”Professor Akram Khan

The central conflict of the program feels a bit like it was engineered by Self, or at least made inevitable by his deliberately-cultivated ignorance. Why, for example, does he wait until halfway through the walk to ask for the basic overview of particle physics that he feels he’s missing, unless it adds to the drama he wants to create? By the end of the program, he admits that asking for explanations when he hasn’t learned much background is a bit unfair. But the trouble is not whether he knows the mathematics. The trouble, rather, is that he’s listened to a typical, very short summary of why we care about particle physics, and taken it literally. He has decided in advance that CERN is a quasi-religious entity that’s somehow prepared to answer big philosophical questions, and never quite reconsiders the discussion based on what’s actually on offer.

If his point is that particle physicists who speak to the public are sometimes careless, he’s absolutely right. We might say we are looking for how or why the universe was created, when really we mean we are learning what it’s made of and the rules for how that stuff interacts, which in turn lets us trace what happened in the past almost (but not quite) back to the moment of the Big Bang. When we say we’re replicating the conditions at that moment, we mean we’re creating particles so massive that they require the energy density that was present back then. We might say that the Higgs boson explains mass, when more precisely it’s part of the model that gives a mechanism for mass to exist in models whose symmetries forbid it. Usually a visit to CERN involves several different explanations from different people, from the high-level and media-savvy down to the technical details of particular systems. Most science journalists would put this information together to present the perspective they wanted, but Self apparently takes everything at face value, and asks everyone he meets for the big picture connections. His narrative is edited to literally cut off technical explanations, because he wants to hear about beauty and philosophy.

Will Self wants the people searching for facts about the universe to also interpret them in the broadest sense, but this is much harder than he implies. As part of a meeting of the UK CMS Collaboration at the University of Bristol last week, I had the opportunity to attend a seminar by Professor James Ladyman, who discussed the philosophy of science and the relationship of working scientists to it. One of the major points he drove home was just how specialized the philosophy of science can be: that the tremendous existing body of work on, for example, interpreting Quantum Mechanics requires years of research and thought which is distinct from learning to do calculations. Very few people have had time to learn both, and their work is important, but great scientific or great philosophical work is usually done by people who have specialized in only one or the other. In fact, we usually specialize a great deal more, into specific kinds of quantum mechanical interactions (e.g. LHC collisions) and specific ways of studying them (particular detectors and interactions).

Toward the end of the final episode, Self finds himself at Voltaire’s chateau near Ferney, France. Here, at last, is what he is looking for: a place where a polymath mused in beautiful surroundings on both philosophy and the natural world. Why have we lost that holistic approach to science? It turns out there are two very good reasons. First, we know an awful lot more than Voltaire did, which requires tremendous specialization discussed above. But second, science and philosophy are no longer the monopoly of rich European men with leisure time. It’s easy to do a bit of everything when you have very few peers and no obligation to complete any specific task. Scientists now have jobs that give them specific roles, working together as a part of a much wider task, in the case of CERN a literally global project. I might dabble in philosophy as an individual, but I recognize that my expertise is limited, and I really enjoy collaborating with my colleagues to cover together all the details we need to learn about the universe.

In Self’s world, physicists should be able to explain their work to writers, artists, and philosophers, and I agree: we should be able to explain it to everyone. But he — or at least, the character he plays in his own story — goes further, implying that scientific work whose goals and methods have not been explained well, or that cannot be recast in aesthetic and moral terms, is intrinsically suspect and potentially valueless. This is a false dichotomy: it’s perfectly possible, even likely, to have important research that is often explained poorly! Ultimately, Self Orbits CERN asks the right questions, but it is too busy musing about what the answers should be to pay attention to what they really are.

For all that, I recommend listening to the five 15-minute episodes. The music is lovely, the story engaging, and the description of the French countryside invigorating. The jokes were great, according to Miranda Sawyer (and you should probably trust her sense of humour rather than the woefully miscalibrated sense of humor that I brought from America). If you agree with me that Self has gone wrong in how he asks questions about science and which answers he expects, well, perhaps you will find some answers or new ideas for yourself.

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Liveblog: New ATLAS Higgs Results

Tuesday, October 7th, 2014

In a short while, starting at 11:00 CEST / 10:00 BST, ATLAS will announce some new Higgs results:

“New Higgs physics results from the ATLAS experiment using the full Run-1 LHC dataset, corresponding to an integrated luminosity of approximately 25 fb-1, of proton-proton collisions at 7 TeV and 8 TeV, will be presented.” [seminar link]

I don’t expect anything earth-shattering, because ATLAS already has preliminary analyses for all the major Higgs channels. They have also submitted final publications for LHC Run I on Higgs decaying to two photons, two b quarks, two Z bosons – so it’s reasonable to guess that Higgs decaying to taus or W’s is going to be covered today.

(Parenthetically, CMS has already published final results for all of the major Higgs decays, because we are faster, stronger, smarter, better looking, and more fun at parties.)

I know folks on ATLAS who are working on things that might be shown today, and they promise they have some new tricks, so I’m hoping things will be fairly interesting. But again, nothing earth-shattering.

I’ll update this very page during the seminar. You should also be able to watch it on the Webcast Service.

10:55 I have a front row seat in the CERN Council Chamber, which is smaller than the main auditorium that you might be more familiar with. Looks like it will be very, very full.

11:00 Here we go! (Now’s a good time to click the webcast, if you plan to.)

11:03 Yes, it turns out it will be taus and W’s.

11:06 As an entree, look how fabulously successful the Standard Model, including the Higgs, has been:

11:10 Good overview right now over overall Higgs production and decay and the framework we used to understand it. Have any questions I can answer during the seminar? Put them in the comments or write something at me on Twitter.

11:18 We’re learning about the already-released results for Higgs to photons and ZZ first.

11:24 Higgs to bb, the channel I worked on for CMS during Run I. These ATLAS results are quite new and have a lot of nice improvements from their preliminary analysis. Very pretty plot of improved Higgs mass resolution when corrections are made for muons produced inside b-jets.

11:30 Now to Higgs to tau tau, a new result!

11:35 Developments since preliminary analysis include detailed validation of techniques for estimating from data how isolated the taus should be from other things in the detector.

11:36 I hope that doesn’t sound too boring, but this stuff’s important. It’s what we do all day, not just counting sigmas.

11:37 4.5 sigma evidence (only 3.5 expected) for the Higgs coupling to the tau lepton!

11:39 Their signal is a bit bigger than the SM predicts, but still very consistent with it. And now on to WW, also new.

11:41 In other news, the Nobel Prize in Physics will be announced in 4 minutes: It’s very unlikely to be for anything in this talk.

11:44 Fixed last comment: “likely” –> “unlikely”. Heh.

11:48 When the W’s decay to a lepton and an invisible neutrino, you can’t measure a “Higgs peak” like we do when it decays to photons or Z’s. So you have to do very careful work to make sure that a misunderstanding of you background (i.e. non-Higgs processes) produces what looks like a Higgs signal.

11:50 Background-subtracted result does show a clear Higgs excess over the SM backgrounds. This will be a pretty strong result.

11:51 6.1 sigma for H –> WW –> lvlv. 3.2 sigma for VBF production mechanism. Very consistent with the SM again.

11:52 Lots of very nice, detailed work here. But the universe has no surprises for us today.

11:54 We can still look forward to the final ATLAS combination of all Higgs channels, but we know it’s going to look an awful lot like the Standard Model. Congratulations to my ATLAS colleagues on their hard work.

11:56 By the way, you can read the slides on the seminar link.

12:02 The most significant result here might actually be the single-channel observation of the Vector Boson Fusion production mechanism. The Higgs boson really is behaving the way the Standard Model says it should! Signing off here, time for lunch

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The World’s Largest Detector?

Wednesday, August 13th, 2014

This morning, the @CERN_JOBS twitter feed tells us that the ATLAS experiment is the world’s largest detector:

CERN_JOBS Tweet Largest Detector

Weighing over 7,000 tons, 46 meters long, and 25 meters high, ATLAS is without a doubt the particle detector with the greatest volume ever built at a collider. I should point out, though, that my experiment, the Compact Muon Solenoid, is almost twice as heavy at over 12,000 tons:

CMS

CMS is smaller but heavier — which may be why we call it “compact.” What’s the difference? Well, it’s tough to tell from the pictures, in which CMS is open for tours and ATLAS is under construction, but the big difference is in the muon systems. CMS has short gaps between muon-detecting chambers, while ATLAS has a lot of space in order to allow muons to travel further and get a better measurement. That means that a lot of the volume of ATLAS is actually empty air! ATLAS folks often say that if you could somehow make it watertight, it would float; as a CMS member, I heartily recommend attempting to do this and seeing if it works. ;)

But the truth is that all this cross-LHC rivalry is small potatoes compared to another sort of detector: the ones that search for neutrinos require absolutely enormous volumes of material to get those ghostlike particles to interact even occasionally! For example, here’s IceCube:

"Icecube-architecture-diagram2009" by Nasa-verve - IceCube Science Team - Francis Halzen, Department of Physics, University of Wisconsin. Licensed under Creative Commons Attribution 3.0 via Wikimedia Commons - https://commons.wikimedia.org/wiki/File:Icecube-architecture-diagram2009.PNG#mediaviewer/File:Icecube-architecture-diagram2009.PNG

Most of its detecting volume is actually antarctic ice! Does that count? If it does, there may be a far bigger detector still. To follow that story, check out this 2012 post by Michael Duvernois: The Largest Neutrino Detector.

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How Can We Hangout Better?

Wednesday, July 9th, 2014

Yesterday we had one of our regular Hangouts with CERN, live from ICHEP, at which we took questions from around the Internet and updated everyone on the latest results, live here at the ICEHP 2014 conference. You can see a replay here:

I sent it to my wife, like I usually do. (“Look, I’m on ‘TV’ again!”) And she told me something interesting: she didn’t really get too much out of it. As we discussed it, it became clear that that was because we really did try to give the latest news on different analyses from ICHEP. Although we (hopefully) kept the level of the discussion general, the importance of the different things we look for would be tough to follow unless you keep up with particle physics regularly. We do tend to get more viewers and more enthusiasm when the message is more general, and a lot of the questions we get are quite general as well. Sometimes it seems like we get “Do extra dimensions really exist?” almost every time we have a hangout. We don’t want to answer that every time!

So the question is: how do we provide you with an engaging discussion while also covering new ground? We want people who watch every hangout to learn something new, but people who haven’t probably would prefer to hear the most exciting and general stuff. The best answer I can come up with is that every hangout should have a balance of the basics with a few new details. But then, part of the fun of the hangouts is that they’re unscripted and have specialist guests who can report directly on what they’ve been doing, so we actually can’t balance anything too carefully.

So are we doing the best we can with a tough but interesting format? Should we organize our discussions and the questions we choose differently? Your suggestions are appreciated!

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My First Day at ICHEP (Again)

Thursday, July 3rd, 2014

ICHEPstartICHEP 2014 started today in Valencia, Spain. This is one of particle physics’s biggest conferences, held every two years. The last one, in 2012, coincided with the discovery of the Higgs boson. This year, we’re probably going to have more in the way of careful measurements than big new surprises. ATLAS and CMS have already released Higgs updates, and the pesky boson looks more and more like the Standard Model Higgs all the time.

This is the second ICHEP I’ve attended in person. I showed a poster at the first one, and wrote a blog post about it – which is a scary reminder of just how long I’ve been blogging. (I also still have my lanyard from that conference, which I’m wearing with my badge because it’s cooler than the boring black one we got this time.) This year, I’m here to give a parallel talk about the potential for even better measurements of the Higgs at the High-Luminosity LHC, which is a possible upgrade for the LHC that could take us well into the 2030s. By then, I suppose I should aspire to give an ICHEP plenary talk. ;)

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The Trees, the Forest, and Scientific Consensus

Tuesday, June 17th, 2014

I recently saw this comic from Twisted Doodles, which I think poses quite a conundrum for our usual simple picture of how science is studied and brought forth into the public:

From http://www.twisteddoodles.com/post/86414780702/working-in-science – used in this post with permission

From Twisted Doodles. Used in this post with permission.

If you are a non-scientist reading this blog, your idea of what science is for, and what it’s good for, is probably something like the left column – and in fact, I hope it is! But as someone who works day-to-day on understanding LHC data, I have a lot of sympathy with the right column. So how can they be reconciled?

Science takes hard work from a lot of people, and it’s an open process. Its ultimate goal is to produce a big picture understanding of a wide range of phenomena, which is what you’re reading about when you think all the good thoughts in the left-hand column. But that big picture is made of lots of individual pieces of work. For example, my colleagues and I worked for months and months on searching for the Higgs boson decaying to bottom quarks. We saw more bottom quarks than you would expect if the Higgs boson weren’t there, but not enough that we could be sure that we had seen any extra. So if you asked me, as an analyzer of detector data, if the Higgs boson existed, all I could say would be, “Well, we have a modest excess in this decay channel.” I might also have said, while I was working on it, “Wow, I’m tired, and I have lots of bugs in my code that still need to be fixed!” That’s the right-hand column.

The gap is bridged by something that’s sometimes called the scientific consensus, in which we put together all the analyses and conclude something like, “Yes, we found a Higgs boson!” There isn’t a single paper that proves it. Whatever our results, the fact that we’re sure we found something comes from the fact that ATLAS and CMS have independently produced the same discovery. The many bits of hard work come together to build a composite picture that we all agree on; the exhausted trees step back to take a broader perspective and see the happy forest.

So which is right? Both are, but not in the same way. The very specific results of individual papers don’t change unless there’s a mistake in them. But the way they’re interpreted can change over time; where once physicists were excited and puzzled by the discovery of new mesons, now we know they’re “just” different ways of putting quarks together.

So we expect the scientific consensus to change, it’s definitely not infallible, and any part of it can be challenged by new discoveries. But you might find that scientists like me are a bit impatient with casual, uninformed challenges to that consensus — it’s based, after all, on a lot of experts thinking and talking about all the evidence available. At the same time, scientific consensus can sometimes be muddled, and newspapers often present the latest tree as a whole new forest. Whether you are a scientist, or just read about science, keep in mind the difference between the forest and the trees. Try to understand which you’re reading about. And remember, ultimately, that the process of doing science is all the things in that comic, all at once.

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In Science, it’s OK to be Wrong

Monday, May 19th, 2014

It’s sort of a recurring theme for me, but a recent Washington Post article on the BICEP2 result, among others, has me wanting to repeat the idea, and keep it short and sweet:

Screen Shot 2014-05-18 at 8.15.54 PM

The issue at hand is whether BICEP2 has really observed the remnants of cosmic inflation, or if in fact they have misinterpreted their results or made a mistake in the corrections to their measurement. It’s frustrating that the normal process of the scientific method – that is, other experts reviewing a result, trying to reproduce it, and looking for holes – is being dramatized as “backlash.” But let’s not worry today about whether we can ever stop the “science news cycle” from being over-sensationalized, because we probably can’t. You and I can still remember a few simple things about science:

1. If scientists think they’ve found something, they should publish it. They should say what they think it means, even if they might be wrong.
2. Other researchers try to replicate the result, or find flaws with it. If flaws are found or it can’t be reproduced, the original scientists have to go back and figure out what’s going on. If other researchers find the same thing, it’s probably right. If lots of other researchers find the same thing, we can agree it’s almost certainly right and move on to the next level of questions.
3. Science makes progress when you say what you know and the certainty with which you know it. If everything you say is always right, you might be being too timid and delaying the process of other researchers building on your results!

But I think Big Bird says it best of all:

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On the Shoulders of…

Monday, April 14th, 2014

My first physics class wasn’t really a class at all. One of my 8th grade teachers noticed me carrying a copy of Kip Thorne’s Black Holes and Time Warps, and invited me to join a free-form book discussion group on physics and math that he was holding with a few older students. His name was Art — and we called him by his first name because I was attending, for want of a concise term that’s more precise, a “hippie” school. It had written evaluations instead of grades and as few tests as possible; it spent class time on student governance; and teachers could spend time on things like, well, discussing books with a few students without worrying about whether it was in the curriculum or on the tests. Art, who sadly passed some years ago, was perhaps best known for organizing the student cafe and its end-of-year trip, but he gave me a really great opportunity. I don’t remember learning anything too specific about physics from the book, or from the discussion group, but I remember being inspired by how wonderful and crazy the universe is.

My second physics class was combined physics and math, with Dan and Lewis. The idea was to put both subjects in context, and we spent a lot of time on working through how to approach problems that we didn’t know an equation for. The price of this was less time to learn the full breadth subjects; I didn’t really learn any electromagnetism in high school, for example.

When I switched to a new high school in 11th grade, the pace changed. There were a lot more things to learn, and a lot more tests. I memorized elements and compounds and reactions for chemistry. I learned calculus and studied a bit more physics on the side. In college, where the physics classes were broad and in depth at the same time, I needed to learn things fast and solve tricky problems too. By now, of course, I’ve learned all the physics I need to know — which is largely knowing who to ask or which books to look in for the things I need but don’t remember.

There are a lot of ways to run schools and to run classes. I really value knowledge, and I think it’s crucial in certain parts of your education to really buckle down and learn the facts and details. I’ve also seen the tremendous worth of taking the time to think about how you solve problems and why they’re interesting to solve in the first place. I’m not a high school teacher, so I don’t think I can tell the professionals how to balance all of those goods, which do sometimes conflict. What I’m sure of, though, is that enthusiasm, attention, and hard work from teachers is a key to success no matter what is being taught. The success of every physicist you will ever see on Quantum Diaries is built on the shoulders of the many people who took the time to teach and inspire them when they were young.

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My Week as a Real Scientist

Thursday, March 6th, 2014

For a week at the end of January, I was a real scientist. Actually, I’m always a real scientist, but only for that week was I tweeting from the @realscientists Twitter account, which has a new scientist each week typing about his or her life and work. I tweeted a lot. I tweeted about the conference I was at. I tweeted about the philosophy of science and religion. I tweeted about how my wife, @CuratorPolly, wasn’t a big fan of me being called the “curator” of the account for the week. I tweeted about airplanes and very possibly bagels. But most of all I tweeted the answers to questions about particle physics and the LHC.

Real Scientists wrote posts for the start and end of my week, and all my tweets for the week are at this Storify page. My regular twitter account, by the way, is @sethzenz.

I was surprised by how many questions people had when I they were told that a real physicist at a relatively high-profile Twitter account was open for questions. A lot of the questions had answers that can already be found, often right here on Quantum Diaries! It got me thinking a bit about different ways to communicate to the public about physics. People really seem to value personal interaction, rather than just looking things up, and they interact a lot with an account that they know is tweeting in “real time.” (I almost never do a tweet per minute with my regular account, because I assume it will annoy people, but it’s what people expect stylistically from the @realscientists account.) So maybe we should do special tweet sessions from one of the CERN-related accounts, like @CMSexperiment, where we get four physicists around one computer for an hour and answer questions. (A lot of museums did a similar thing with #AskACurator day last September.) We’ve also discussed the possibility of doing a AMA on Reddit. And the Hangout with CERN series will be starting again soon!

But while you’re waiting for all that, let me tell you a secret: there are lots of physicists on Twitter. (Lists here and here and here, four-part Symmetry Magazine series here and here and here and here.) And I can’t speak for everyone, but an awful lot of us would answer questions if you had any. Anytime. No special events. Just because we like talking about our work. So leave us comments. Tweet at us. Your odds of getting an answer are pretty good.

In other news, Real Scientists is a finalist for the Shorty Award for social media’s best science. We’ll have to wait and see how they — we? — do in a head-to-head matchup with giants like NASA and Neil deGrasse Tyson. But I think it’s clear that people value hearing directly from researchers, and social media seems to give us more and more ways to communicate every year.

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Which is the Real CERN?

Thursday, December 19th, 2013

Is this CERN...?

Is this CERN…?

Or is this CERN...?

Or is this CERN…?

A few weeks ago, at the very real peril of spending our weekend on something that was a little like work for both of us, I went with my wife to the Collider exhibit at the Science Museum in London.

Collider a detailed, immersive exhibit about the Large Hadron Collider and the people who work on it. It’s amazing to hear video interviews from real physicists and see real places at CERN reproduced. A lot of the information is on realistic-looking whiteboards, and there’s real stuff lying everywhere just like in real offices. (The real stuff is glued and stapled down; my wife, a museum curator interested in the implementation of the exhibit, checked that detail personally.) One thing that bothered me that might not bother you: the videotaped physicists are clearly actors, with stories told just a bit too dramatically. One thing that might bother you but didn’t bother me, because I can skip reading signage and just explain to my wife what I think it should say: not all of the amazing things you could see are explained very well.

But the fun part really is the feeling of actually being in the midst of where the science is done. For example, at right, you can see a picture of me in one of the CERN hallways recreated for the exhibit, and you can see a picture of me in front of the real version of the same office. But which is which?

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