Higgs

Standing in Faraday’s Shoes

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A highlight of my recently-completed visit to England was the honor of giving a public lecture at the Royal Institution of Great Britain in London. It’s an honor to give public talks anywhere, of course — I always enjoy seeing people who are not professional scientists nevertheless decide that the best way they can spend a Tuesday evening is to hear a physicist lecture about the Higgs boson and the Large Hadron Collider. But the RI is special. Its leadership in bringing science to a wide audience dates back to 1825, when Michael Faraday inaugurated the famous Christmas Lectures. The lecture hall where I was speaking is the same one where Faraday spoke, happily with more comfortable seats and better audio-visual equipment. The connection was especially appropriate, as the hidden message (not so hidden by the end, really) of my talk was that we need to think about the world in terms of fields rather than particles, and it was Faraday who introduced the concept of an electric field.

Sadly, almost as soon as I left the RI announced that it is in serious financial difficulty. (I don’t think it was my fault — we had a nearly-full house for the lecture.) Their historic building in the tony Mayfair district of London, where the popularity of their events in the nineteenth century led Albemarle Street to become the first one-way street in the city, is now up for sale. Scientists and science lovers are in an uproar, and hope to save the RI building from being sold to an unsympathetic landlord, but it’s unclear whether that’s a feasible scenario. While it’s true that there are many more outlets for good science communication now than in Faraday’s time (I’m sure he would have been an enthusiastic blogger, but the technology wasn’t quite ready yet), it would certainly be a shame to lose or substantially alter such an historic and effective institution.

For the curious, here is the talk I actually gave, complete with location-specific jokes.

The audience Q&A, a lively discussion moderated by Alok Jha, was recorded separately.

And for the impatient, here is a much more brief (7 minutes) interview that I did just ahead of time.

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Skeptically Speaking

In a few hours I’ll be chatting live on Skeptically Speaking, a weekly podcast and radio show about science and critical thinking. The guest host will be Marie-Claire Shanahan, a science educator who blogs at Boundary Vision. Live broadcast is at 8pm Eastern/5pm Pacific, and before too long the recording will be available as a podcast.

There’s a Canadian theme running through the week, as I just got back from Toronto and Skeptically Speaking is based in Edmonton. Good timing; with global warming hurtling along, it’s the country of the future.

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How to Explain the Higgs Mechanism

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Greetings from chilly Toronto, where I’m briefly in town to participate in a public event about the Higgs boson tonight. Should be a good time, especially because it’s not just me giving a talk; I will spend 20 minutes explaining the theoretical motivation behind the Higgs, after which experimentalists Pierre Savard and William Trischuk will talk about the actual experiments.

Which raises the question: how does one explain the theoretical motivation behind the Higgs, given a small number of minutes and a motivated-but-nonexpert audience? It’s something I should have figured out by now, having written a book and all. But I’ve been fishing around, and I think I’ve finally settled on a favorite approach to doing it.

A couple of preliminary notes. I don’t think there is a good explanation of the Higgs boson at the sound bite level, say 15 seconds or less. That’s because you need to explain two distinct things: first, that there is a Higgs field filling space that interacts with the particles moving through it and giving some of them mass; and second, that the Higgs boson is the particle we observe when we interact with a vibration in that field. Both of these ideas are part of quantum field theory, which we generally don’t try to explain in physics popularizations, so it’s more than a few seconds of work to get them across. But I don’t think there is a shortcut: if you want to explain the Higgs at all, you have to explain the Higgs field.

With that in mind, the biggest stumbling block to providing a convincing popular-level motivation for the Higgs field is that we immediately leap to the idea that the role of the Higgs is to “give particles mass,” where by “particles” we really mean “quarks, charged leptons, and the W & Z bosons.” This raises a couple of problems. First, why do we need some mechanism to give particles mass? Why can’t they just have mass? Of course some particles can just have mass — like the Higgs itself. So you’re starting off by moving backwards, bringing up the need to explain why different symmetries apparently prevent particles from having mass, which is actually harder to explain than the Higgs mechanism. And second, most of the mass in real objects comes from QCD, not from the Higgs mechanism at all, so you are almost inevitably giving people the wrong idea. You see why it’s a tricky situation.

Fortunately, we have an alternative: the actual historical development of the subject. Back in the early 1960’s when the Higgs mechanism was being proposed (by Anderson, Englert, Brout, Higgs, Hagen, Guralnik, and Kibble), they weren’t trying to give mass to fermions. They were trying to explain how nuclear forces, which manifestly only stretch over a very short distance, could possibly be described in a way similar to gravity and electromagnetism (i.e. by Yang-Mills theories), which manifestly stretch over long distances. Sure, both gravity and E&M fade away as you move farther from a source, but they do so slowly (the inverse square law, in particular), which is why they are relatively easy to observe in the everyday world. If the nuclear forces are simply generalizations of E&M, as Yang and Mills suggested, why don’t they stretch over large distances? …

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How to Explain the Higgs Mechanism Read More »

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Colbert Redux

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Last night I had the privilege of once again appearing on the Colbert Report to talk with our nation’s leading pundit about the frontiers of modern science. Here’s the clip. I’m not sure you’d want to use it to help explain how the Higgs mechanism works, but I think we had fun. The joke about “massive” at the end makes sense only if you know that Colbert has a running gag, referenced earlier in the show, in which he has been trying to get people to say “massive” as a synonym for “cool.”

The Colbert Report Mon – Thurs 11:30pm / 10:30c
Sean Carroll
www.colbertnation.com
Colbert Report Full Episodes Political Humor & Satire Blog Video Archive

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Reviews!

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Many writerly friends of mine swear with a straight face that they never look at reviews of their books. I have tried but failed to comprehend the inner workings of these alien minds; personally, as much as I know it might pain me, I can’t help but read reviews. Sometimes I might even learn something! Or at least be gratified, in this nice review of The Particle at the End of the Universe by Adam Frank at NPR.

Or, on the other hand, simply be amazed and astonished. The most amusing “review” so far has come from one of the good readers at Amazon, working under the nom de plume “Chosenbygrace Notworks,” and coming with the to-the-point title “Arrogant atheist `science’.” Apparently Chosenbygrace is not handicapped by actually having read the book, but did hear me talk on Coast to Coast AM. Here’s the opening:

Sean Carroll is a typical atheist physicist who arrogantly disregards creationists to the point where he does not even acknowledge they exist unless prompted (like happened on Coast to Coast AM tonight). The liberal media and filled with money sapping money-obsessed morons like this, willing to indebt any generation of Americans into becoming slaves. It’s already happened, and Americans in general are all debt slaves because of atheism-theoretical-physics cultists like this, and the idiot atheists who worship delusional morons like this.

It goes on, but, you know, probably the gist has been conveyed. The physics/atheism connection is a classic, of course, but I hadn’t been aware that we in the cult were also responsible for plunging Americans into debt. 5 out of 425 people found the review helpful, so at least someone is being helped! (In fairness, the Amazon review by Ashutosh Jogalekar probably does a better job of conveying what’s in the book than any I’ve yet seen.)

Other reviews are puzzling, and I have to mention one in particular. …

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Reviews! Read More »

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Shindig!

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This afternoon, 6pm Eastern/3pm Pacific, is the fun event I mentioned before: a “virtual book tour” discussion on a new-ish platform called Shindig. The idea is that I sit here with my webcam, talking to you and showing some pictures; you sit where you are, with your own webcam, as a potentially-participatory audience member. You can virtually “raise your hand” to ask a question, either by text or by audio in the post-talk Q&A. Different audience members can break off into groups to chat about things by themselves. It’s all free and open and quite experimental, so we’re trying to coax as many people into participating as possible. Certainly saves time (and fossil fuels) in comparison to jetting around the country.

The topic, of course, will be the new book, or really just the basics of the Higgs search and the Large Hadron Collider. I will give a brief overview, very casual, and anyone there should feel free to ask whatever they like.

Here’s an example of a Shindig event, featuring A.J. Jacobs.

Should be fun. Join us if you can!

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A Book Full of Particles

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Publication day! In case it’s slipped your mind, today is the day when The Particle at the End of the Universe officially goes on sale. Books get a bit of a boost if they climb up the Amazon rankings on the first day, so if you are so inclined, today would be the day to click that button. Also: great holiday present for the whole family!

A very nice review by Michael Brooks appeared in New Scientist. (It’s always good to read a review when you can tell the author actually read the book.) Another good one by John Butterworth appeared in Nature, but behind a paywall.

Brief reminder of fun upcoming events:

  • Today (Tuesday the 13th), you can Ask Me Anything over at Reddit, starting at 2pm Eastern, 11am Pacific. Of course you lovely blog readers already know everything worth knowing, but I’m looking forward to dodging personal queries from people around the world. (And hopefully explaining a little physics.)
  • Thursday I’ll be doing an online chat in a platform called Shindig. That’s 6pm Eastern, 3pm Pacific. Fire up your webcam and you can be part of the virtual audience.

FAQ: Yes, you should have no trouble reading and understanding it, no matter what your physics background may be. Yes, there are electronic editions of various forms. Yes, there will also be an audio book, but it’s still being recorded. No, nobody has yet purchased the movie rights; call me. Yes, I know that the Higgs boson is not literally sitting there at the end of the universe. It’s a metaphor; for more explanation, read the book!

Writing this book has been quite an experience. Unlike From Eternity to Here, in this case I wasn’t writing about my own research interests. So for much of the time I was acting like a journalist, talking to the people who really built the Large Hadron Collider and do the experiments there. It’s no exaggeration that I went into the project with an enormous amount of respect for what they accomplished, and came out with enormously more than that. It’s a truly amazing achievement on the part of thousands of dedicated people who are largely anonymous to the outside world. (But for the rest of their lives they get to say “I helped discover the Higgs boson,” which is pretty cool.)

Of course, being who I am, I couldn’t help but take the opportunity to try to explain some physics that doesn’t often get explained. So once you hit the halfway point in the book or so, we start digging into what quantum field theory really is, why symmetry breaking is important, and the fascinating history of how the Higgs mechanism was developed. (I had to restrain myself from going even deeper, especially into issues of spin and chirality, but this is supposed to be a bodice-ripper, not a brain-flattener.) At the end of the book, as a reward, you get to contemplate the role of the internet and bloggers in the changing landscape of scientific communication, as well as all the fun technological breakthroughs that we will get as a result of the Higgs discovery. (I.e., none whatsoever.)

Sean Carroll: The Particle at the End of the Universe

Hope you like reading it as much as I liked writing it.

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Avoid the Christmas Rush!

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Hard to believe I wrote another book. How did that happen? But it must be true, as The Particle at the End of the Universe is now available for pre-order on Amazon and elsewhere. Back to real work for me, for the foreseeable future. (Unless someone wants to give me a million dollars, which to date they have been reluctant to do.)

I’m actually putting finishing touches on the copyediting as we speak. Events have prodded the publisher to move up the release date quite a bit (as I expected), so now it’s coming out in November rather than in February. So we’ve been in a mad dash against the clock, although I’ve tried my best to be careful in the actual writing. And many people have been extremely generous with their time, reading over chapters and talking with me about the issues. Compared to From Eternity to Here, this book is obviously less about presenting a novel take on some deep issues in physics and more about helping people understand why the Higgs boson is important, and how the experiments actually look for the thing. But there are a couple of chapters in there where I get to try to explain gauge invariance, connections, and symmetry breaking. I can’t help myself; it’s in my nature.

Speaking of generosity, even with the short timescale I scored pretty big with the back-cover blurbs. Check these out:

“In this superb book, Sean Carroll provides a fascinating and lucid look at the most mysterious and important particle in nature, and the experiment that revealed it. Anyone with an interest in physics should read this, and join him in examining the new worlds of physics to which this discovery may lead.”

–Leonard Mlodinow, author of The Drunkard’s Walk

“Carroll tells the story of the particle that everyone has heard of but few of us actually understand. After you read his book — an enticing cocktail of personal anecdote, clever analogy, and a small dose of mind-bending theory — you will truly grasp why the Higgs boson has been sought after for so long by so many. Carroll is a believer in big science asking big questions and his beliefs are infectious and inspiring.”

–Morgan Freeman, Actor and Executive Producer of Through the Wormhole

“The science is authoritative, yet bold and lively. The narrative is richly documented, yet full of human drama. Carroll’s saga pulls you aboard a modern voyage of discovery.”

–Frank Wilczek, winner of the Nobel Prize in Physics

If only the actual writing in the book could be that good! “Obtain blurbs from Oscar winner and Nobel laureate for same book” is now checked off my bucket list.

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Higgs Papers Out

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We were all transfixed by the Higgs seminars on July 4, but the work was nowhere near over for the experimentalists — they had to actually write up papers describing the results. And of course taking the opportunity to do a little more analysis along the way.

Now the papers have appeared on the arxiv. (Via lots of places, e.g. symmetry breaking and Matt Strassler.) Here’s ATLAS:

Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC

The ATLAS Collaboration
(Submitted on 31 Jul 2012)

A search for the Standard Model Higgs boson in proton-proton collisions with the ATLAS detector at the LHC is presented. The datasets used correspond to integrated luminosities of approximately 4.8 fb^-1 collected at sqrt(s) = 7 TeV in 2011 and 5.8 fb^-1 at sqrt(s) = 8 TeV in 2012. Individual searches in the channels H->ZZ^(*)->llll, H->gamma gamma and H->WW->e nu mu nu in the 8 TeV data are combined with previously published results of searches for H->ZZ^(*), WW^(*), bbbar and tau^+tau^- in the 7 TeV data and results from improved analyses of the H->ZZ^(*)->llll and H->gamma gamma channels in the 7 TeV data. Clear evidence for the production of a neutral boson with a measured mass of 126.0 +/- 0.4(stat) +/- 0.4(sys) GeV is presented. This observation, which has a significance of 5.9 standard deviations, corresponding to a background fluctuation probability of 1.7×10^-9, is compatible with the production and decay of the Standard Model Higgs boson.

And here’s CMS:

Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC

The CMS Collaboration
(Submitted on 31 Jul 2012)
Results are presented from searches for the standard model Higgs boson in proton-proton collisions at sqrt(s)=7 and 8 TeV in the CMS experiment at the LHC, using data samples corresponding to integrated luminosities of up to 5.1 inverse femtobarns at 7 TeV and 5.3 inverse femtobarns at 8 TeV. The search is performed in five decay modes: gamma gamma, ZZ, WW, tau tau, and b b-bar. An excess of events is observed above the expected background, a local significance of 5.0 standard deviations, at a mass near 125 GeV, signalling the production of a new particle. The expected significance for a standard model Higgs boson of that mass is 5.8 standard deviations. The excess is most significant in the two decay modes with the best mass resolution, gamma gamma and ZZ; a fit to these signals gives a mass of 125.3 +/- 0.4 (stat.) +/- 0.5 (syst.) GeV. The decay to two photons indicates that the new particle is a boson with spin different from one.

…

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