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Seth Zenz | Imperial College London | UK

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Nerds and Names

Thursday, July 16th, 2015

If there’s one thing that makes me jealous about planetary scientists, it’s how many things they get to name. They also seem to have an awful lot of fun with it. Consider these typical naming processes:

  • Experimental particle physicists: “Jeff Weiss did an ‘availability search” of the Greek alphabet and found that the Greek letter Upsilon was not yet used”. [1]
  • Planetary scientists: “Woooooooo, another mountain range! Let me get my copy of the Silmarillion!” [2]

They also seem to have snuck in a Marvel Cinematic Universe tie-in while naming one of Pluto’s newer moons.

Hydra_Revealed_Tweet

But wait, you may ask, doesn’t particle physics have whimsical names?  A few, sure. But it was the theoretical physicists who named things like “quarks”; by the time we discover them, we already know what they’re supposed to be and don’t get to make up new names.  New particles with 5 quarks?  We’ll just be literal and call them “pentaquarks”; the specific states can be Pc(4450)+ and Pc(4380)+[3], names which give useful information about charge and mass but aren’t really any fun.  Really, the most fun we ever get to have is with tortured acronyms [4].  It’s just not fair at all.

But seriously, congratulations to everyone working on New Horizons.  Enjoy your fun — you’ve earned it. And maybe the next particle we discover, we’ll take a page from your playbook.

[1] J. Yoh (1998). “The Discovery of the b Quark at Fermilab in 1977: The Experiment Coordinator’s Story“. AIP Conference Proceedings 424: 29–42.

[2] Not an actual quote (as far as I know). But since yesterday, Pluto has a “Cthulhu” and a “Balrog” and Charon has a “Mordor”.

[3] See Adrian Davis’s Quantum Diaries post from yesterday.

[4] ATLAS Collaboration (2008). “The ATLAS experiment at the Large Hadron Collider.” JINST 3 S08003. See the acronym list appendix.

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Choose as Many as You Like

Tuesday, April 7th, 2015

I want to understand the universe.

I want to understand how the universe works.

I want to build models of how the universe works that predict the results of experiments.

I want to build models of how the universe works that predict the results of experiments, because I believe those models get closer and closer to the truth.

I want to build models of how the universe works that predict the results of experiments, because I believe those models get closer and closer to the true rules of reality.

I want to build models of how the universe works that predict the results of experiments, because I believe that although it’s unknowable whether reality has “true” rules, building better and better models is the closest we can get.

I want to build models of how the universe works that predict the results of experiments, because I believe that understanding the true rules of reality will help us understand why the universe exists.

I want to build models of how the universe works that predict the results of experiments, because I believe that understanding the true rules of reality will shed light on the Creator of the universe.

I want to build models of how the universe works that predict the results of experiments, because I believe that the more we can explain without religion the less people will rely on it.

I want to build models of how the universe works that are simple and beautiful.

I want to build models of how the universe works that are simple and beautiful, because these models have the best track record of predicting the broadest range of experimental results.

I want to build models of how the universe works that are simple and beautiful, because I believe the true rules of reality are simple and beautiful.

I want to understand enough of how the universe works that I can build machines to improve people’s lives.

I want to understand enough of how the universe works that I can find new ways to save lives and heal the sick and injured.

I want to understand enough of how the universe works that I can help us stop endangering the climate of our planet.

I want to understand how the universe works so that other people can someday find new practical ways to improve and save lives, even if I don’t quite know what they are and probably won’t work on them myself.

I want to build machines for studying how the universe works, because I find working on those machines to be challenging and fulfilling.

I want to write programs for analyzing data from experiments on how the universe works, because I find analyzing data to be challenging and fulfilling.

Choose as many as you like. If other people want to hear about it, tell them – or, if you prefer, don’t. And if you have more you’d like to add, leave them in the comments!

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On Being an Artwork

Thursday, March 19th, 2015

Back when we were discussing Will Self’s impression of CERN as a place where scientists had no interest in the important philosophical questions, I commented that part of the trouble was Self’s expectation that scientists who were expecting to give him a technical tour should be prepared to have an ad hoc philosophical discussion instead. I also mentioned that many physicists can and will give interviews on broader topics. What I didn’t mention is that I included myself, because I had already done an interview in 2014 on the “existential” boundaries of physics knowledge. I didn’t know at the time that that interview had already been made part of an art installation! I ran across the installation by chance recently, and I think it’s worth taking a close look at because it provides a positive example of substantive engagement between art, philosophy, and science.

The installation is “sub specie aeternitatis”, by Rosalind McLachlan. It is described in a review for Axisweb by Matthew Hearn as “seek[ing] greater understanding not through belief in the knowable, but in asking scientists to address the limitations of their field and forcing them to consider the ‘existential horror’ – the problems of our existence in terms of what we can’t know.” It features five CERN physicists talking all at once on separate screens about questions that physics can’t necessarily answer. If I remember correctly, it looks like mine was “What happened before the Big Bang?”

I didn’t get to see the exhibit itself, but the review makes it clear that the installation went far beyond simply showing video of the interviewees. The artist made conscious decisions about how to weave our words and surroundings together:

Whilst at any one moment only a single voice plays, thinking aloud – struggling to find meaning – collectively all five characters appear to be working together, evolving a visual language of gesture and animated body movement, grasping to find some shared form of resolution. CERN has been celebrated for the way international communities collaborate, put individual agendas aside, and share knowledge and understanding, and the visual simultaneity within McLachlan’s installation captures this collegiate approach.

The piece thus presents the core values of international collaborative science in a novel way, beyond the mere words scientists usually use to explain it. But it isn’t a new allegory divorced from actual scientists at CERN and our work: it still uses our own words, mannerisms, and office whiteboards to build the impression. What a wonderful example of how art can add new dimensions to communicating about science!

Looking at my part of an excerpt from the installation video, it’s clear why I’m in it. Not so much because of what I’m saying – a lot of it is explained better on Sean Carroll’s blog, even if I do disagree with him sometimes on philosophical interpretations. But because of how I’m saying it: slowly, with long deliberate pauses that allow the other screens to speak and give the impression that I’m working things out as I go along. What I was really doing is working how best to communicate my ideas, but this installation isn’t replicating life as literally as a documentary would. It does replicate how some physicists think about science and philosophy, and how we work together, and I think that’s remarkable.

Links

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Day in the #PostdocLife

Tuesday, February 3rd, 2015

Recently, my wife, a.k.a. Polly Putnam, Collections Curator at Historic Royal Palaces, did a post for A Day in the Creative Life, a Tumblr page organized by the Department of Culture, Media, and Sport. So I thought I would borrow an idea from them and post about a day in my life. I’ve left the word “Creative” out of my own title, but it’s worth noting that scientific work is still very creative. I work every day on original ways to slice and dice data collected by the Compact Muon Solenoid (CMS) detector at CERN’s Large Hadron Collider (LHC); a lot of creative work goes into achieving that goal.

It’s also a team effort. As I go through the play-by-play of my day, you’ll see there are a lot of meetings and conversations and emails. Indeed, people often joke that CMS stands for Continuous Meeting Society! You might be tempted to see this as overly bureaucratic, but I hope to it will come across to you that the way we organize ourselves is a necessary approach to worldwide collaboration on one of the biggest of Big Science experiments there is. Just in a single day, the colleagues I interact directly with are in America, the UK, France, Switzerland, India, and China.

06:00 Wake up, in the darkness, slightly later than usual.

07:00 Out the door and warming up the car. Normally my wife would drive me to the train station, which is just across the river from the palace she works at, but today she’s at home and I’ll drive myself. This is scary, because most of the driving I’ve done in my life was on an automatic transmission in the United States — here, I have to deal with the clutch, drive on the left side of the road, and deal with far less space than I’m used to.

07:24 My first train leaves Hampton Court Station. I sit down and resume reading Seeing White, a textbook recommended by Harvard Astronomy Professor John Asher Johnson as a starting point for learning how to help address racial inequity in science and beyond. My trip involves changing trains once and a bit of a walk through London at the end.

08:30 I arrive at the office at Imperial College London and take stock of my day, especially the emails about the meeting I’m leading in 90 minutes.

09:00 Chat with colleagues about their contributions to the aforementioned meeting.

09:30 Throw together my own “news” slides outlining the status of the project and how people can help.

10:00 Go to a meeting room and “phone in” to the meeting I organize, where we work on preparing software for “Higgs to Gamma Gamma” — that is, to (re)discover and study the Higgs boson decaying into pairs of photons when LHC Run 2 starts this summer. I give my overview, others give more detailed talks on their progress, and we discuss what we need to do next.

11:00 Breathing a sigh of relief, I finally start on a bit of actual work for a new project I’m helping with. “Actual work” usually means, to me, writing and testing C++ code, although at the moment I’m also editing a wiki page so that colleagues can follow along with what I’ve figured it out. While my code is compiling I correspond with colleagues who want to contribute to my other project — informal discussion meetings are set up for tomorrow, which will also be “by phone.”

11:30 I grab a sandwich and eat it, along with delicious roast vegetable stew.

12:30 On “the phone” with another colleague, talking about handing off a coding task that I originally planned to start on but no longer have time for. After walking through what I know so far, I promise to help as needed with the details.

13:15 More interleaved emails and bits of coding.

14:30 I drop in on one of the academics I work with. As a senior postdoc, I do most of my work — and even help organize others’ work — mostly independently, but the overall priorities of CMS and my research group are set by more senior folks. I go to them with questions or just to check in about my overall progress and next steps.

14:40 Start a major edit of the instructions on my new project, testing each step as I go.

15:00 “Phone in” to the general Higgs to Gamma Gamma meeting. This is a broader meeting than the working meeting in the morning, where I can keep track of other work on analysis development and preparation for the next LHC run, as well as the analyses that continue on the data we already have.

15:03 Computer crashes. Reboot in a panic, phone back into meeting just in time for it to start.

15:20 Realize the instructions I was editing were lost in the reboot. Restart from where I last saved and repeat my work as I listen to presentations in the meeting.

17:00 After the meeting ends, I finish my documentation and check in with the person organizing that project. Check back in to help the colleague I talked to at 12:30.

17:45 Process an email with new code for the Higgs to Gamma Gamma analysis framework. Check that it works before adding it to the overall project.

18:05 Start going home. Have several train mishaps but eventually sneak on. Work on a bit of blogging when I finally get a seat.

19:15 Get off the train, get in the car, and go grocery shopping.

20:15 Supper. Couples’ Minecraft. Eventually, sleep.

And then I start it all again the next day.

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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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