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How I learned to stop worrying and love reductionism
July 2, 2012 11:45 PM   Subscribe

Scientists at CERN, using the Large Hadron Collider, may have discovered the Higgs Boson. (previously) and (previously)
posted by AElfwine Evenstar (157 comments total) 26 users marked this as a favorite

 
My GF works for the National Academy of Sciences. Her read on the mood of her co-workers regarding this: "Eh. Nobody too surprised or excited. Doesn't mean what people are going to try to say it means, and we knew it was coming for a while now."

Note: I am not a scientist and I think this is cool. Just reporting the facts as I understand them.
posted by Navelgazer at 11:48 PM on July 2, 2012


I'll believe it when I see observe it.
posted by njloof at 11:49 PM on July 2, 2012 [3 favorites]


I feel so guilty that I can't ever not read it as "Large Hardon Collider," and always wind up thinking of contexts that that phrase could be marketed profitably in.

Most of them, really.
posted by DoctorFedora at 11:51 PM on July 2, 2012 [6 favorites]


(To put that another way, apparently to them this is sort of like having another nice piece of evidence for Evolution. Every scientist there already knows/believes that the Higgs Boson is real, and this isn't going to change much. Still cool, though.)
posted by Navelgazer at 11:51 PM on July 2, 2012


May.
posted by Neale at 11:56 PM on July 2, 2012 [1 favorite]


Remember when people thought that the Large Hadron Collider would destroy the world?

Does this news mean we are one step closer?
posted by twoleftfeet at 11:57 PM on July 2, 2012


Life, now with less Technicolor.
posted by Bighappyfunhouse at 11:58 PM on July 2, 2012


If almost every scientist thought the Higgs Boson already existed, and everyone in the community is not too excited, why the $9 billion outlay for the Large Hadron Collider?
posted by thecjm at 11:58 PM on July 2, 2012 [2 favorites]


The "have" link gives a pretty good idea of what is currently going on as far as the procedure the physicists go through when operating the LHC and why progress is so slow.
posted by AElfwine Evenstar at 11:59 PM on July 2, 2012


If almost every scientist thought the Higgs Boson already existed, and everyone in the community is not too excited, why the $9 billion outlay for the Large Hadron Collider?

The Higgs Boson - A Tales from the Road Comic
posted by vidur at 12:00 AM on July 3, 2012 [16 favorites]


They've already found the Higgs; it's just not been a strong enough statistical certainty to announce. Hopefully this means the latest set of data analysis has pushed it 'over the top' to be beyond doubt.

Though I'm not looking forward to the media reaction.

reality: "Scientist confirms existence of Higgs; physics continues to work as we thought, but now we know."

media: "Boffins discover new particle that makes everything heavy at atom smasher in switzerland! Physics revolutionized! Is time travel and faster than light speed now possible? Our quack says it is!"
posted by ArkhanJG at 12:02 AM on July 3, 2012 [32 favorites]


thecjm: I'm not saying "everyone" or "every scientist." I'm relaying what I heard today when my girlfriend got home from work at a place that employs a lot of top scientists.

By my understanding this is another valuable piece of evidence to strengthen a theory and help it move forward, but not "we have observed this thing" like laymen might be expecting.
posted by Navelgazer at 12:04 AM on July 3, 2012 [1 favorite]


Obligatory xkcd comics 1, 2, 3.
posted by tzikeh at 12:13 AM on July 3, 2012


ArkhanJG: "media: "Boffins discover new particle that makes everything heavy at atom smasher in switzerland! Physics revolutionized! Is time travel and faster than light speed now possible? Our quack says it is!""

If only you could work the "missing link" into that somehow.
posted by brundlefly at 12:15 AM on July 3, 2012 [1 favorite]


If God turns out to be a particle after all this, I'm going to be really pissed off.
posted by bicyclefish at 12:17 AM on July 3, 2012 [1 favorite]



If almost every scientist thought the Higgs Boson already existed, and everyone in the community is not too excited, why the $9 billion outlay for the Large Hadron Collider?

By this reasoning then there would be very little science done at all. Things must be tested and confirmed whether there's a 1% chance it exists or even if we think its 100% there. Progress would be amazingly slow if we just assumed what most people thought was right and only go back and investigate if there is a problem in the future. Science can be a slow process, but it marches forward. Its important we check to see where we are so that we don't have to retrace our steps to get back on track.
posted by Phantomx at 12:19 AM on July 3, 2012 [6 favorites]


Scientists Report Major Finding On Higgs-Boson, Secure Funding In Tanking European Economy.
posted by Tell Me No Lies at 12:21 AM on July 3, 2012 [3 favorites]


Quantum Diaries (linked at the word "have" above) is going to live-blog the update from CERN at the International Conference on High Energy Physics in Melbourne tomorrow.

They sound pretty excited to me.
posted by gingerest at 12:21 AM on July 3, 2012


If almost every scientist thought the Higgs Boson already existed, and everyone in the community is not too excited, why the $9 billion outlay for the Large Hadron Collider?

The standard model predicts the higgs; we already had a reasonably good idea of where it should be. But science is about theorise-test-confirm. (or theorise-test-hmm what is THAT?).

Without the LHC, we couldn't test for the Higgs. So far we've not confirmed it, though there's a candidate that's already pretty damn close to being confirmed. You have to prove the theory through experimentation. If we hadn't found the Higgs, that would mean either the standard model was wrong, or we were looking in the wrong place - either way, that would mean some fairly heavy tinkering in our current theory.

The LHC isn't just looking for the Higgs though; there's a whole ton of other experiments going on at the different detectors. It's the most powerful atom smasher we've ever built, and gives us insight into several areas of physics we'd not been previously able to examine experimentally - dark matter, the big bang, string theory and the unified field theory are all areas we're getting new data on with the LHC.

As a side effect of the LHC, we've also built a huge data storage and transmission network to deal with the utterly vast amount of data and make it available for analysis which in and of itself has been stretching IT capabilities to new levels.

We haven't even run it at full whack yet - it's going to be upgraded to run at the full 7TeV its capable of over the next couple of years.

Scientists are excited about the Higgs; but it was pretty close to confirmed months ago. Still, I bet there are some very excited physicists at CERN who are finally able to confirm something they've spent a number of years working on.
posted by ArkhanJG at 12:25 AM on July 3, 2012 [5 favorites]


atom particle smasher. Sorry, got tripped up by my own media frenzy.
posted by ArkhanJG at 12:31 AM on July 3, 2012 [1 favorite]


I always thought "God Particle" was just short for "Omygod Particle".

Still, there are many other rumors about what they'll be announcing that you can see at the Twitter hashtag #HiggsRumors, some of which I have been contributing...
Prefers to be called "Higgy" #HiggsRumors

Secretly funding SuperPac for de-funding Science programs just so people will leave it alone! #HiggsRumors

Was discovered in a post-credits scene in "Ted" #HiggsRumors

Is a hipster. #HiggsRumors

When formally introduced, requests that you not stare at its Boson #HiggsRumors

Considers the term 'particle' demeaning, prefers to be called 'thingy'. #HiggsRumors

Always watched Community on Thursday instead of Big Bang Theory #HiggsRumors
Told pollster it's still undecided. #HiggsRumors

Ghost-wrote fifth draft of Prometheus script, inserting plot holes just to confuse anybody #HiggsRumors

Was not the butler in Magnum PI after all. #HiggsRumors #HigginsRumors
posted by oneswellfoop at 12:31 AM on July 3, 2012 [4 favorites]


I was playing devils advocate a bit. I'm all for the LHC and thing nations don't spend nearly enough on science.

But for such a big, expensive project, I'd like to see more people in lab coats dancing in the streets when it produces results instead of another monotone lecture on how this is just another small step in furthering human knowledge.
posted by thecjm at 12:32 AM on July 3, 2012 [1 favorite]


Are we entirely sure the world isn't already being destroyed in some insidious subtle way we have yet to detect? Are we sure the Higgs Boson did not cause the financial crisis? How about this heat wave? Maybe an eathquake here and there? It knows we are on to it, that is why we have to catch it and destroy it before it destroys us.
posted by Ad hominem at 12:36 AM on July 3, 2012 [3 favorites]


Has there been a study done on the inaccuracy of popular science headlines?
posted by crapmatic at 12:37 AM on July 3, 2012


How do we know Obama is not the Higgs Boson. It is so crazy it just might be true.
posted by Ad hominem at 12:37 AM on July 3, 2012


It is so crazy it just might be true.

It would be great if the Theory of Physics actually worked that way. And sometimes it does. "Hey wacko longhair patent examiner... if one twin is traveling near the speed of light then he won't age as much as his brother who stayed on Earth!" It's so crazy it just might be true!

"Hey longhair heretic Italian dude, what if a feather and a bowling dropped from a height actually reached the ground at the same time?" It's so crazy it might be true!

The "it's so crazy it might be true" thing should be a fundamental principle of scientific inquiry, because it's so crazy it might be true!
posted by twoleftfeet at 12:51 AM on July 3, 2012 [1 favorite]


How do we know Obama is not the Higgs Boson.

Well, they're both defined by the state of their spin....

(I'll show myself out....)
posted by tzikeh at 12:53 AM on July 3, 2012 [15 favorites]


I always thought "God Particle" was just short for "Omygod Particle".

It's short for "goddamn particle" due to the difficulty in pinning it down.
The God Particle is the title of a popular science book by Nobel Prize winner Leon Lederman, who was Fermilab's director for many years and thus my boss when I was a postdoctoral fellow there. According to Leon, he wanted to call the book The Goddamn Particle because nobody could find the thing. However, his editor discouraged him from the title, suggesting that The God Particle would sell many more copies. This is the story that Leon tells us.
posted by floam at 12:53 AM on July 3, 2012 [5 favorites]


bowling ball. There's actually little evidence that Galileo dropped a bowling ball off the Leaning Tower of Pisa. But it's so crazy it might be true!
posted by twoleftfeet at 12:53 AM on July 3, 2012


But for such a big, expensive project, I'd like to see more people in lab coats dancing in the streets when it produces results instead of another monotone lecture on how this is just another small step in furthering human knowledge.

Oh, trust me, there will be celebrations. Maybe not exactly dancing and fireworks, but there'll be champagne at the very least, and most importantly, the feeling that we'll finally have removed that thorn that has stuck in the side of theoretical physics for so long. Because no matter how beautiful a theory is, no matter how perfectly all the components fit together, you'll never know it is right before it has been experimentally verified in the laboratory. And once that has been achieved, hopefully numerous times, you can base even more intricate, powerful theories on that one (in this case, the Standard Model). You will also finally know that whatever new things you discover in the future, it has to fundamentally conform to the basic SM picture of the universe, so in that sense you have some kind of sanity check on your work.

My department, which has been heavily involved in the research into pixel silicon detectors at ATLAS, has planned a special seminar tomorrow at which the press conference at CERN will be broadcast live. Although I am currently not at located at my home institution, I have been tempted to travel back just for that occasion; it will be a special hour indeed, in my opinion.
posted by Anderson_Localized at 12:59 AM on July 3, 2012


It kind of irks me how this is constantly reported as "Scientists at CERN in Switzerland have discovered..." when it is really a global effort. Scientists at Fermi Lab in Illinois and the KEK Lab in Japan among others world wide have contributed hugely to the construction of the LHC as well as analysis of the data it produces and should share in the credit for this discovery.
posted by j03 at 1:01 AM on July 3, 2012 [3 favorites]


Will no one think of the boson? I mean, maybe the Higgs Boson is just happy to do its thing without tons of attention. Maybe we are just hurting the boson population by continually hunting for it. What if the boson became extinct? We should just leave the boson alone.

Sorry. I thought we were talking about bison.
posted by twoleftfeet at 1:09 AM on July 3, 2012 [2 favorites]


Here's the Bison. (And yes, I own the shirt and will be wearing it tomorrow)
posted by oneswellfoop at 1:13 AM on July 3, 2012 [1 favorite]


Hug these bison. They helped find the Higgs.
posted by j03 at 1:17 AM on July 3, 2012 [2 favorites]


ArkhanJG: reality: "Scientist confirms existence of Higgs; physics continues to work as we thought, but now we know."

John Timmer, over at Ars, says that, while rumor claims we're seeing the Higgs at about 125GeV, so far it's not behaving quite the way we expected. He says this hints at new physics we don't know yet. We've known for awhile that there must be another layer to the onion, since we don't yet understand gravity, but the Higgs not responding as expected might be a big flashing arrow on where to start looking.

So, at least if rumor can be believed, it's about the best of all possible results: an extremely fundamental hypothesis is confirmed, but it's only partially confirmed. There's something up there, but it's not doing quite what we thought it would. And, lo and behold, we have an absolutely perfect machine for figuring out what's going on.

As Isaac Asimov said on more than one occasion, the really important stuff doesn't happen when a scientist shouts "Eureka!" The truly exciting things happen when a scientist says, "Hmm. That's funny."
posted by Malor at 1:19 AM on July 3, 2012 [23 favorites]


I heartily recommend two documentaries for those of you interested in LHC and/or Higgs:

* BBC Horizon's "The Six Billion Dollar Experiment" from May 2007. Sadly it's no longer available from the BBC online, however it's out there unofficially for those who know where to look. Produced before the LHC officially went online, it has absolutely gorgeous shots of the LHC, high production values, and an excellent overview of the project. It even has Brian Cox! Short preview here.

* BBC Horizon's "The Hunt for Higgs", from Feb 2012, about the Higgs Boson search itself. Explains how the experiments were narrowing down the possible GeV mass range of the particle, and how it would soon be either found, or disproved to exist.
posted by ceribus peribus at 1:29 AM on July 3, 2012 [6 favorites]


Scientists Report Major Finding On Higgs-Boson, Secure Funding In Tanking European Economy.

Specifically, "bazillions of euros": The Dog Particle. (Not actually to be taken as editorial commentary or criticism from me... I'm just hugely amused that this is actually hosted at the National Institutes of Health .gov website.)
posted by taz at 1:33 AM on July 3, 2012 [1 favorite]


Since we're recommending documentaries... Don't leave out the PBS documentary The Atom Smashers.
posted by j03 at 1:47 AM on July 3, 2012 [2 favorites]


Remember when people thought that the Large Hadron Collider would destroy the world?

I came here from a world where there was no empirical evidence for the Higgs Boson. My world is no more!

In other news, you can't cross the same river twice.
posted by Kid Charlemagne at 1:48 AM on July 3, 2012 [1 favorite]


So when do we get the comedy Twitter feed, @HiggsBoson, where it claims it wasn't even hiding?

(does quick twitter search) Protected? Dagnabbit!
posted by JHarris at 2:01 AM on July 3, 2012 [1 favorite]


But for such a big, expensive project, I'd like to see more people in lab coats dancing in the streets
I don't think particle physicists much need lab coats, and my experience with physicists in general is they require an awful lot of coaxing to get them to dance in public. (I didn't plan it that way, but somehow most of my collegiate love life revolved around physicists. So I do have a sample, albeit a small and biased one.)

How about a really excited lecture with a lot of math in it, as a compromise? I am pretty sure I know where you can get several of those tomorrow.
posted by gingerest at 2:06 AM on July 3, 2012 [1 favorite]


I heard that it's nothing to do with the Higgs and the conference title is actually "More Funny Things You Can Say After Inhaling Helium".

"Higgs Boson" sounds hilarious in a squeaky voice.
posted by milkb0at at 2:29 AM on July 3, 2012 [2 favorites]


One femtobarn is 10-43 m2, which is a thousandth of a millionth of a millionth the diameter of a uranium nucleus. An inverse femtobarn is the number of particle collisions per femtobarn. So 10 inverse femtobarns is equal to 10 collisions per 10-43 m2. That's the density of collisions recorded thus far in the LHC.

Before it was shut down, the Tevatron at Fermilab had also accumulated 10 inverse femtobarns worth of data, but because the collisions at Fermilab were done at lower-energy, they would have produced substantially fewer Higgs-Bosons, making the certainty of any resulting conclusions statistically weaker.
posted by dephlogisticated at 2:42 AM on July 3, 2012 [1 favorite]


If God turns out to be a particle after all this, I'm going to be really pissed off.

God is both a wave AND a particle.

God is both a wave AND a particle AND a Shetland pony.
posted by Lipstick Thespian at 3:09 AM on July 3, 2012 [1 favorite]


So the Higgs gives other particles mass, but the Higgs has a mass of about 125GeV/c2? What gives the Higgs its mass then, eh? Answer that, scientists!

It's Higgs bosons all the way down, I tell you.
posted by edd at 3:18 AM on July 3, 2012 [2 favorites]


God is both a wave AND a particle AND a Shetland pony.

And a breath mint. And a floor wax AND a desert topping.
posted by oneswellfoop at 3:56 AM on July 3, 2012 [5 favorites]


Higgs bosoms.
posted by flippant at 3:57 AM on July 3, 2012 [1 favorite]


Physicists knew the Higgs was there but didn't necessarily know what form it would take or what it's properties would be, especially the mass. There could have been a super symmetric higgs, which would have meant three different higgs particles at different masses, and would have had a bunch of follow on implications.
posted by empath at 5:12 AM on July 3, 2012


Meanwhile, over at Brookhaven...
posted by Thorzdad at 5:21 AM on July 3, 2012 [1 favorite]


It's important to note that the CERN folks haven't actually announced their results yet. Rumors are flying, but we won't know anything for sure until the official announcement tomorrow at 9 AM CEDT (3 AM EST.) The scientists at Fermilab (not CERN) have announced results that are suggestive, but not as definitive as the CERN results are expected to be.

In other words, don't go splashing those "HIGGS BOSONS STRUCK DOWN" banners on your blogs just yet.
posted by Johnny Assay at 5:28 AM on July 3, 2012


Before it was shut down, the Tevatron at Fermilab had also accumulated 10 inverse femtobarns worth of data, but because the collisions at Fermilab were done at lower-energy, they would have produced substantially fewer Higgs-Bosons, making the certainty of any resulting conclusions statistically weaker.

But, amusingly enough, maybe easier to see. There are certain Higgs forming reactions that ATLAS and CMS at the LHC really can't see, because the background noise, caused by the higher energy beams, is too high. But the lower energy beams of the TeVatron gave CDF and D0 a lower energy beam.

They didn't get the discovery -- you need 5σ, and they only found a 2.9σ difference between predicted background, in a region that hasn't been ruled out by other data. So close, alas. Only a 1 in 550 chance that this isn't a real signal, but the standard is 1 in 10000.

I always thought "God Particle" was just short for "Omygod Particle

No. The "Oh My God Particle" refers to ultra-high energy cosmic particles. To give you an idea about ultra high: One particle spotted, probably a proton, had an energy of 3x1020 eV, or 50 joules. 50J is the energy in a baseball thrown at 60mph.
posted by eriko at 5:48 AM on July 3, 2012 [3 favorites]


Et voilà, a leak has sprung.
posted by dharp at 5:57 AM on July 3, 2012


It's actually the M. Boson, with the ability to perform flying torpedoes and chew scenery.
posted by Strange Interlude at 6:09 AM on July 3, 2012 [1 favorite]


God is both a wave AND a particle AND a Shetland pony.

And a breath mint. And a floor wax AND a desert topping.


It changes a sandwich into a banquet. It gets rid of your traveler's cheques.
posted by Dark Messiah at 6:16 AM on July 3, 2012


Boson Buddies would be a great name for a sitcom about cross-dressing CERN scientists.
posted by emelenjr at 6:17 AM on July 3, 2012 [3 favorites]


The only problem is that it's already an awesome documentary about that very subject.
posted by Anything at 6:20 AM on July 3, 2012


A rap musical documentary.
posted by Anything at 6:21 AM on July 3, 2012


"Only a 1 in 550 chance that this isn't a real signal, but the standard is 1 in 10000. "
This misrepresents the meaning of a p-value. It tells you the probability that the signal could come about by chance if the real signal is not present. It's P(D|H0) - the probability of the data given that the null hypothesis is true. It's already assuming that the signal is false in order to calculate the probability so it obviously can't tell you the probability that the signal is false.
That's not to say it is not an important factor in calculating the probability that the signal is real - which would be P(H1|D) - but the p-value does not immediately translate to it. You need to use Bayes' Theorem to make the conversion along with some other information, or at least some other guesses.

This is also why I've personally considered the Higgs already detected since the previous CERN results were announced, even if it's not 'industry standard' to do so.
posted by edd at 6:27 AM on July 3, 2012


ArkhanJG: "They've already found the Higgs; it's just not been a strong enough statistical certainty to announce. Hopefully this means the latest set of data analysis has pushed it 'over the top' to be beyond doubt.

Though I'm not looking forward to the media reaction.

reality: "Scientist confirms existence of Higgs; physics continues to work as we thought, but now we know."

media: "Boffins discover new GOD particle that makes everything heavy at atom smasher in switzerland! Physics revolutionized! Is time travel and faster than light speed now possible? Our quack says it is!"
"

FTFY ... and the actual story where it got the name from being called "That God Damned Particle" but they had to sanitize it for the mainstream and thus all this stupid name that stuck with the public fascination...
posted by symbioid at 6:29 AM on July 3, 2012


vidur: "Comic"

Also holy shit that's awesome - everyone, go read that now! I like to read about physics from time to time, but that really did a great job explaining the process and shit.
posted by symbioid at 6:38 AM on July 3, 2012


"Physicists Discover 'God Particle' in Switzerland - Religion Scientifically Proven"
posted by xbonesgt at 6:41 AM on July 3, 2012 [1 favorite]


This makes me so happy, because what else would a God Particle be called but Higgs. Naturally Higgs is this sort of rangy guy with patchy facial hair who is drinking a really great double americano out of a Mason jar. He is looking up through space and time at the whitecoated dudes, smiles a little and says, "hey... having a good time, checking things out? that's great. well, keep looking, there's lots more stuff to see, and if you have any question's that's cool... you're supposed to have questions. peace."
posted by seanmpuckett at 6:56 AM on July 3, 2012


"Physicists Discover 'God Particle' in Switzerland - Religion Scientifically Proven"

"...but very, very small"
posted by A Thousand Baited Hooks at 7:13 AM on July 3, 2012 [1 favorite]


Higgs looks like this. Which works pretty well for several reasons.
posted by zoinks at 7:16 AM on July 3, 2012


If God turns out to be a particle after all this, I'm going to be really pissed off.
posted by bicyclefish
So does that mean God would be Particle Man?
posted by blaneyphoto at 7:30 AM on July 3, 2012


CERN needs to learn how to manage communications. The news in the linked Discover article is "On Wednesday (July 4), scientists heading two major experiments at the LHC plan to announce...". They plan to announce, tomorrow, and on a major holiday in the US at that. They will be announcing new results that have been dribbling out for a few days and we already have scientists on the record saying what they found but it's all a bit confusing and hazy. And this after last year's announcement that they sort of found something, itself preceded by weeks of dribbling leaks.

I get that real science is messy. But then treat it that way and communicate early and often. Why is there no CERN blog to focus the informal, pre-announcement discussion? Rich irony that CERN doesn't understand how to use the Web to communicate to the public.
posted by Nelson at 7:35 AM on July 3, 2012


Particle Man (SLYT)
posted by VTX at 7:41 AM on July 3, 2012 [1 favorite]


Ms Particle Man: a game to find the Higgs Boson available for iPhone and iPad and MS Silverlight
posted by j03 at 8:01 AM on July 3, 2012


Hi gang, (one of) your friendly neighborhood particle physicists checking in.

Holy shit, things have been crazy in the lead up to this. We're too busy to dance in the streets right now, but everyone is very excited, continually asking about the latest rumors and bothering their local experimentalist (who tend to be very close-lipped; I think ATLAS and CMS have hit squads out for those who talk). I know of several Higgsmas parties tonight organized by physicists (the CERN announcement is at 9 am Geneva time, or 2 am at Fermilab where I work), and everyone who can be will be up to watch the talks. The discovery of the Higgs is something that most of my colleagues have been waiting for for literally their entire careers (which, considering that you often hear the phrase "as you all learned in kindergarten" used to describe quantum mechanics, gets easily conflated with one's entire life).

On top of the excitement, everyone is also trying to rush out papers related to the new results as soon as they become available, so there's actual work to be done, and the competition will be fierce.

So at some point today, completely insanity at work permitting, I'll try to explain in some detail the physics behind the Higgs boson. Right now I'll say that, while we know SOMETHING exists that does the job of the Higgs (give fermions mass, breaks electroweak symmetry), we don't actually yet know what that thing is. The Higgs boson is the "simplest" version, but Nature never has to make life easy, so it's important for our understanding of particle physics to find this thing and measure its properties precisely. So while tonight they may announce discovery of "the Higgs," what they'll really be announcing is the discovery of a particle that has a mass in the right general range, and some decay modes that match our broad expectations. You should keep in mind it will take a lot longer to confirm that this thing is indeed the Higgs, though that will certainly get lost in the pop sci coverage. Either way, it'll be very exciting.

Now, what will they announce tonight? Frankly, I don't really know, and (barring leaks from Nature - the journal, not the Universe) no one outside the experiments does either.

What is known is that, during the winter conferences last year, both ATLAS and CMS saw statistical fluctuations above background expectations in several channels that are associated with the Higgs (the Higgs decays almost immediately, so you look for the decay products; the LHC results are driven by higgs to photon/photon and higgs to W/W mostly. I'll talk about this more later if I have the time). Both experiments saw these excesses in basically the same place, corresponding to a mass of about 125 GeV (a proton weighs about 1 GeV).

These upward fluctuations could be due to background, as events don't come with a little flag saying "I'm a Higgs." Furthermore, as we don't know the mass of the Higgs (only a range of possible masses consistent with our understanding of the rest of particle physics), upward fluctuations ANYWHERE in the range of possible masses could be confused with a real signal. So there's a "look elsewhere effect," which means that any individual possible signal is less statistically significant than it would be if there was no other measurement at a different Higgs mass. With this effect included, this is a 2-3 sigma result from each experiment (meaning that the observations are expected to have been a result of a background fluctuation only 2% or 0.1% of the time). 5 sigma is the "gold standard" for discovery in particle physics. You can estimate the result of two independent experiments combining their results by adding in quadrature (though this is a bit dodgy, so its only a rule of thumb), so the previous CMS and ATLAS combined result was expected to be sqrt(2^2+3^2) = 3.6 sigma.

The Tevatron, when it shut down, had a slight excess in different modes (higgs to b/anti-b quarks, which are difficult to measure at the LHC right now) in the same mass range. Yesterday we saw a talk by the two Tevatron experiments (CDF and DZero), their statistical significance for this bump is 3 sigma combined, which will grow if they can remove the look-elsewhere effect (say, if the LHC discovers the Higgs at 125 GeV). So the American accelerator can tell us a lot still, especially as it will take a long time for the analysis techniques at the LHC to evolve to a point where they can see h->bb over the huge background, but as we are no longer collecting events, we can only do so much.

Simple extrapolation from the amount of data available from the previous LHC results to today (combined with an improvement in beam energy from 3.5 TeV to 4 TeV in each proton, so 8 TeV collisions instead of 7 TeV), implies that each experiment *should* have about 4 sigma evidence tonight. This falls short of the 5 sigma magic number, but this is only an estimate. Improvement in analysis techniques or statistical fluctuations could bring us above that line for each experiment. Furthermore, if each experiment is "close enough," CERN might break protocol and announce discovery in sufficiently hedged terms. Or, they've rushed a combined analysis, which would certainly break the 5 sigma line, assuming that the results are consistent with what we saw previously. I personally think this last is unlikely, but they may have had the combination working groups on triple overtime for the last few weeks.

This is all speculation, and I might look like a total idiot at 2 am tomorrow. What is known is that Higgs and the other theorists responsible for the theoretical discovery of the Higgs mechanism are in CERN today; they presumably wouldn't have been asked to be there without good reason.

Finally, as noted, there are some oddities in the current results, which could imply that this is not the Standard Model Higgs (though it still could be the Higgs, just with modified interactions). While this would be awesome news, we should keep our expectations in check as the statistical significance of those results are a bit overstated. It's very easy for us to be mislead at this point; we will know more in a few hours though.

Nelson: CERN is a European lab; while there is a joke going around right now that the timing was chosen especially to fuck with the American physicists, for Europe, July 4 is just another work day. ICHEP, one big worldwide particle physics conference is starting next week in Australia, so that is the likely driver for the timing of this announcement.

Furthermore, the way these experiments work is by "blinding" themselves to their results. They cannot announce results before they have locked in their analysis, done the work, "opened the box" to see what they have, and then double-check their work and have the collaboration "bless" the final conclusions. Analysis was continuing through this week, and probably is still going on right now. This is how it's supposed to be done, and the rumors are just that: rumors. The rest of the physics community wants answers more than the public, but we have to respect how the experimentalists do things to avoid biasing themselves. The internet has improved scientific collaboration by leaps and bounds (I cannot imagine working before arxiv, for example), but some times in science, you cannot let everyone see everything you are doing until the final results are in (at which point, of course, you have to open your books for the rest of us to pore over).

As I said, this is a very busy day for me, I really hope I can get back in a few hours and answer any questions that come up, and try to explain more about the Higgs mechanism and what it means for particle physics. It's a very exciting time, the results from the LHC have been amazing, and I'm really happy to see so many non-physicists so interested in our work. Because really, physics is awesome.
posted by physicsmatt at 8:28 AM on July 3, 2012 [58 favorites]


CERN is a European lab; while there is a joke going around right now that the timing was chosen especially to fuck with the American physicists, for Europe, July 4 is just another work day
I have heard from a friend at CERN that, as with the last announcement, the room is going to be utterly packed (especially as some seating is reserved for certain VIPs). He expects that if he wanted to go he'd have to be queueing hours in advance of the 9am start. A 5am start waiting to get into a lecture hall for hours is not just another day for them!

He also suggests ICHEP as a reason for the timing, incidentally.
posted by edd at 8:37 AM on July 3, 2012


edd, yeah, this isn't another day at work for any of us, but that was in response to the idea that a European lab is going to do their scheduling around an American holiday.

I'm really worried that their stream of the announcement will be unavailable as everyone in the world with the slightest interest in physics will be watching it.
posted by physicsmatt at 8:41 AM on July 3, 2012


I hope that whoever their sufficiently important person is that they've chosen to make the announcement walks up on stage, grabs the mic and says, "We found it." drops the mic and walks off. Maybe post the same thing on Twitter and whatever other social media is relevant.

If this isn't for the confirmation of the Higgs-Boson, I hope that's how they do it when they're ready.
posted by VTX at 8:54 AM on July 3, 2012


Yep, I'm worried about the stream being heavily overloaded too. I'll be lucky to get a 2σ detection of any 4σ detection.
posted by edd at 8:58 AM on July 3, 2012


If almost every scientist thought the Higgs Boson already existed, and everyone in the community is not too excited, why the $9 billion outlay for the Large Hadron Collider?
posted by thecjm at 8:58 AM


Because science does not operate on faith.
posted by CautionToTheWind at 9:01 AM on July 3, 2012 [6 favorites]


The vixra blog has some nice information about the Higgs search, particularly about hints of beyond-standard model physics in the data (though to me a lot of that sounds like hopeful thinking at this point).
posted by pombe at 9:46 AM on July 3, 2012 [1 favorite]


surely once it is found the higgs boson will bring about an end to starvation, human cruelty, poverty, weeping and gnashing of teeth and restore the universe to a state of everlasting peace and harmony. which is cool, cuz then we won't have to concern ourselves with fixing that shit.
posted by quonsar II: smock fishpants and the temple of foon at 9:52 AM on July 3, 2012


I worked at one of the LHC Tier 1 computing centres. I'm a sysadmin, not a physicist, so don't expect insights into the physics, but...

- The timing is all about ICHEP. ATLAS and CMS have been pushing hard to get work done in the last few weeks, to make sure they can get their papers written in time.
- The feed of the press conference might not be great on your laptop. CERN are rationing the bandwidth, with more going to organised events. The lab where I work will is screening the press conference in a lecture theatre.
- ATLAS and CMS are keeping things pretty tight, to the extent that even our experiment reps claim not to know the full story.
posted by Urtylug at 10:25 AM on July 3, 2012 [1 favorite]


Err, that is to say, I WORK at an LHC Tier 1 computing centre.
posted by Urtylug at 10:32 AM on July 3, 2012


So...do we ever get to start calling it a graviton? That's what it is, right?
posted by sexyrobot at 10:58 AM on July 3, 2012


No, the graviton is something else.
posted by Mitrovarr at 11:09 AM on July 3, 2012


The Higgs bassoon itself produces only notes that were too low to be detected until now, yet it is responsible for the notes produced by all other musical instruments.
posted by DevilsAdvocate at 11:23 AM on July 3, 2012 [7 favorites]


Not only is the Higgs not the graviton, you wouldn't expect a graviton to be detectable as a particle with anything remotely approaching practical technology.
posted by edd at 11:27 AM on July 3, 2012


The Higgs bassoon: The Fundamental fundamental.
posted by Jode at 12:04 PM on July 3, 2012


Stop calling it the “God Particle!”
posted by homunculus at 12:16 PM on July 3, 2012 [1 favorite]


So does that mean God would be Particle Man?

God is God-Man.
posted by homunculus at 12:20 PM on July 3, 2012


I know of several Higgsmas parties tonight organized by physicists

There's an unalloyed joy in the process of science, and in scientists in general, that I enjoy so very much, and this sentence sort of encapsulates the entire thing.
posted by Malor at 12:49 PM on July 3, 2012 [3 favorites]


Scientist discover large concentration of Higgs-Boson in the trunk of a 1964 Chevy Malibu last seen leaving New Mexico for LA #HiggsRumors

Higgs-Boson discovered to be just confusing symbolism in new M. Night Shyamalan movie. Twist: Charm quark actually strange #HiggsRumors
posted by MiltonRandKalman at 2:19 PM on July 3, 2012


Based on the PhD Comics link about CERN and the HB posted upthread, it seems that the "Higgs field" is a lot like the "ether" of pre-Einstein physics. Both "permeate the entire universe" and provide a medium through which other particles must move. Can anyone give a short explanation of how these two concepts are similar/different?
posted by captain cosine at 3:20 PM on July 3, 2012


CERN might have accidentally Mourdocked themselves (oops I just verbed a proper name?) - an announcement video has leaked but they're claiming they made one for each possibility...
posted by RedOrGreen at 3:36 PM on July 3, 2012


Things can only get better
can only get better
now I've found the Higgs boson
posted by Anything at 3:38 PM on July 3, 2012


Both "permeate the entire universe" and provide a medium through which other particles must move.

All fields permeate the entire universe. It's still doesn't provide a preferred reference frame, though, which is what the ether was all about.
posted by empath at 4:00 PM on July 3, 2012


CERN is a European lab; while there is a joke going around right now that the timing was chosen especially to fuck with the American physicists, for Europe, July 4 is just another work day. ICHEP, one big worldwide particle physics conference is starting next week in Australia, so that is the likely driver for the timing of this announcement.

Not next week. ICHEP opens today. The CERN announcement will be broadcast by two-way video at the conference welcome reception, at 17:00 Melbourne time (09:00 CET, dark o'clock in the morning in the US).
The timing is explicitly and totally about ICHEP.
posted by gingerest at 5:37 PM on July 3, 2012


Question: what is the difference between the Higgs and the theoretical existence of a graviton, which mediates the force of gravity? It sounds like the Higgs is to mass as photons are to charge. That sounds like a graviton to me! I'll go google now, but maybe someone here knows...
posted by TreeRooster at 6:00 PM on July 3, 2012


Ok, I did find this, which definitely says there is a difference. Also, I guess it should be gravitons:mass::photons:charge. However, it still sounds like Higgs:Higgs-field::photons:electromagnetic-field. I may be confusing force fields with some other sort of field. If photons pop up as localizations of the EM field, and then carry force, then if Higgs bosons pop up as localizations of the Higgs field, do they not mediate any sort of force? I guess the answer must be "no," rather they mediate something else entirely...somehow bequeathing mass.
posted by TreeRooster at 6:22 PM on July 3, 2012


"Hey longhair heretic Italian dude, what if a feather and a bowling dropped from a height actually reached the ground at the same time?" It's so crazy it might be true!

Maybe a lead feather.
posted by Sparx at 7:27 PM on July 3, 2012 [1 favorite]


t-minus 3 hours and 20 minutes. Getting excited, but feeling alienated as all my friends and family can't understand what I'm so excited about.
posted by AElfwine Evenstar at 8:39 PM on July 3, 2012


OK, let me try to explain the Higgs boson. To give a good explanation requires a lot of background, and I'm going to try not to half-ass it.

There are 4 forces of nature: gravity, the electroweak nuclear force, the strong nuclear force, and something called hypercharge. Electromagnetism is actually a combination of two of these forces: the electroweak and hypercharge forces, it's intimately related to the Higgs, and we'll get there.

Each force acts at a distance between particles that are charged under the relevant force by exchanging "force carriers." You can picture this as two people throwing a ball back and forth; the momentum carried by the ball will push each person around. This doesn't explain why forces can be attractive, but the picture isn't bad to start with. The important point is: a force requires a particle to carry it.

I'll pretty much ignore gravity for now, since that's a difficult one to deal with. It's a very weak force, so we can't create or see the force carriers - the gravitons - easily, and there are some additional technical problems that make quantization of gravity difficult. Thus there is string theory, but moving on.

The remaining forces are very similar in certain respects: they are all carried by spin-1 particles called "vector bosons" (the boson means they have integer spin and obey a certain type of spin statistics - the alternative is a fermion with half-integer spin - and the vector refers to their spin-1-ness). You can prove that, given our understanding of quantum field theory, the force carriers MUST be vector bosons. Also, by spin here, I do mean spin as you know it: angular momentum. If you got hit by enough vector bosons carrying coherent spin, you'd start rotating. The force carriers are: the B for hypercharge, the gluons for the strong force, and the W1, W2, and W3 for the electroweak force.

Furthermore, you can prove that each force carrier is massless. This allows the forces to be infinite range. Handwaving a bit, due to the uncertainty principle, you can "borrow" energy from the Universe to create a particle as long as you pay it back in some time inversely related to how much energy you borrowed. There's an important relation here: large energies thus correspond to short times and short distances. So the Universe can "borrow" arbitrarily little energy to create a massless particle, and not have to pay it back for infinitely long times, allowing the force to be propagated over huge distances. Handwaving, I know, but it gets the right general behavior.

However, when you look at the gauge bosons we actually find in Nature, it's nothing like this. Ignoring the gluons, which have their own craziness, we find that hypercharge and electroweak bosons are all mixed up together. The thing we call the photon is actually a combination of the B and the W3. There's another combination of these two that we call the Z. The W1 and W2 are typically combined in two ways: one combination is a particle called the W+ with positive electric charge, and the other is the W- with negative electric charge. Even worse, the W's and Z are massive: the W's weigh 80 GeV, and the Z is 92 GeV. This is particularly bad when you learn that massless gauge bosons have two possible states: +1 and -1 spin orientation, while a massive gauge boson must have three: +1, 0 and -1. Where did the extra state come from?

In other words, what just happened?

The answer is the Higgs field. If there was a field (which is just a set of values everywhere in the Universe. The electrons are described by a field, as are gluons, photons, and every other particle) that was charged under both electoweak and hypercharge forces, then both the B and the W1, W2, W3 would interact with it. Most fields relax back to zero values if you don't pump energy into them to create a particle. However, if this special field interacts with itself in a particular way, then it is actually energetically favorable for this field to not sit a zero, but to have a non-zero value everywhere. So, everywhere around you, where you think there is empty space, there is actually a field with some "vacuum expectation value" (vev). This field we call the Higgs field.

Since the Higgs field happens to have both electroweak charge and hypercharge, if one of these gauge bosons tries to travel through the Universe, it sees a space full of stuff that it wants to interact with. The W's and the Z therefore gain a mass: it's harder for them to move through the Universe, and so if you want to create one of these particles you have to dump a lot more energy into a region of space, and they would propagate slower as they push through this background field. That's one good definition of mass: if something has mass, I can't create a particle with arbitrarily little energy (as E = mc^2), and it will move slower than light.

What about the photon? Well, it turns out due to the structure of the electroweak and hypercharge forces, that the Higgs has a bit of a choice in how it obtains its vev. Way back when, when the Universe was very hot, the Higgs field floated freely away from this minimum, but as it cooled, at some point in the Universe, it settled into a particular "direction." This means that some combination of W3 and B sees the vev, and so is impeded in its progress, and gains mass. The other combination is "just right" to avoid interacting with the combination of hypercharge and electroweak charge of the Higgs vev. This one remains massless, and we call it the photon. The combination of charges it interacts with is called electric charge, and this is the electromagnetic force we know. We know it BECAUSE the photon is massless; as a result the force is long range, and thus capable of affecting our day-to-day lives.

The other combination, the Z, couples to a combination of hypercharge and the electroweak charge, which you can rewrite as a (different) combination of electric charge and electroweak charge. The W+ and W- couple only to electroweak charge; but since they themselves have electroweak charge, they get interactions with the photon and Z. That's why we use the + and - notation for them: they now have electric charge. Using our handwaving of the infinite range of massless forces, this means that massive force carriers make the force short-ranged: the particles can't travel very far before their "borrowed" energy has to be paid back. This is why the weak force is weak: because the force carriers responsible for it are incredibly short range (like 10^-18 m short).

Now, what about those extra states for the Z and W?

If you take any quantum field, and throw energy into it, you'll get an excitation: a particle. Now, to get the breaking of electroweak and hypercharge, the higgs field needs to be a scalar (spin-0), complex (real + imaginary numbers), and a "electroweak doublet." That's 4 states total: two charged under electromagnetism, and two neutral. Three get "eaten" by the W+, the W-, and the Z, becoming their zero angular momentum mode, and thus making up the extra states . So a Ws and Z we see with spin-0 are actually "the higgs," or at least, part of the higgs. So we've already seen 3/4 of the Higgs field. It's just that one last, non-eaten Higgs.

So, the job of the Higgs is to break the electroweak and hypercharge forces into two new forces: electromagnetism and the weak force. It makes the gauge carriers of the weak for heavy, making the weak force… weak. The key term here is "electroweak symmetry breaking" or EWSB. SOMETHING in the Universe has to be breaking the forces in this manner, so there is absolutely something very similar to the Higgs field out there. It has to have a particular arrangement of charges, and provides the extra states for the W and Z. However, it doesn't have to be as simple as this minimal Higgs I just described.

But what about mass? Everyone hears about how the Higgs "gives everything mass," and so far I've just said a lot about mixing up charges and forces, and yes, it gives mass to the W and Z, but what about the rest of the Universe.

Turns out, the Higgs doesn't give mass to everything. A proton has a mass of 0.980 GeV. Of that, only about 0.01 GeV can be attributed to the Higgs. The rest is is due to strong force interactions. Without the Higgs, your body would be only about 1% lighter. You would not notice however, since you'd be busy dissolving into ions as every electron zipped off at the speed of light.

What the Higgs does (or, what it does in addition to EWSB) is give mass to the fundamental fermions (spin-1/2 particles): the electron, the up quark, the down quark, the muon, and so on (not the proton or the neutron, they are made up of quarks and gluons and are not fundamental). Why is this so? and why does it matter?

It turns out that the Higgs gives mass to fermions due to another, totally bizarre, fact about the Universe. A spin-1/2 particle can be divided up into two possible states: one with +1/2 angular momentum in a particular direction (say in the direction it is moving in), and one with -1/2 spin in that direction. Let's call the first set "right-handed" and the second "left-handed" (RH and LH for short). Now, you'd think that a RH and a LH electron (for example), are the same particle, just spinning in opposite directions. And in a sane universe, they would be. In our universe, they are not.

The LH state interacts with hypercharge and electroweak charge. The RH state interacts only with hypercharge. Weirder still, the hypercharge of the RH state isn't even the same as that of the LH one. This means that any of these wacky fermions can't be massive.

Why is that? Well, if you run past something rotating clockwise (that's right-handed angular momentum) and look back, you'll see it rotating counterclockwise (left-handed momentum). So the only way an electron can have mass if it has both LH and RH states. But it doesn't: there's an e_L and and e_R, but they aren't the same thing. So both e_L and e_R zip along at the speed of light, and this is fine, since you can't "run past" a particle moving at the speed of light.

The Higgs, it turns out, has exactly the right set of quantum numbers to balance the difference between the LH and RH states of fermions. And not just the electron. The quarks as well, even though the assignment of charges is different, the difference between LH and RH is still exactly the same as for electrons, and exactly the charges that the Higgs has. Even odder at first glance, the combination that wasn't broken by the Higgs: electromagnetism? Well, both LH and RH fields have the same electric charge. So once the Higgs obtains its vev, an e_L zipping along can interact with the background field, "shed" the excess hypercharge and weak charge, and leave as an e_R (or vice versa), all the while have electric charge of -1. The stronger that interaction with the Higgs background field, the "slower" the particle wants to go, and so the more massive the particle is. (I've been writing this as if there is an absolute frame of reference; there isn't, and nothing here requires there to be one. Unfortunately, it's hard enough to do this explanation at this level, doing it while remaining Lorentz invariant is beyond my skills. The point is, the Higgs is not the ether).

So you see the incredibly intricate nature of the Standard Model of particle physics. At high energies, the Universe seems to have completely different forces, with particles that interacted completely differently than they appear to down at the low energies where we live. Once the Higgs gets a vev though, you mix up the forces, leaving one combination as the photon, and giving mass to the other combinations. Then, it just so happens that the field that does that magic trick also has the right properties to give all the fermions mass, even though that doesn't seem quite related.

Of course, we physicists are always looking for a better answer than "wow, that's complicated." If you look at this intertwined structure, you can sort of see patterns emerging; one possible set of patterns allows you to unify all the forces together (just as electomagnetism and weak forces look separate at low energies, but unify at high energies, as I've described, you can do the same trick again with the strong, weak and hypercharge forces, and unify them all). Such models are called Grand Unified Theories (GUTs), and we have quite sorted them out yet (the more obvious ones make predictions that turn out to be wrong in our universe), but the gauge structure of the Standard Model is just crying out for something like this.

Also, I've described the minimal Higgs. There are more complicated models (for example, TWO Higgses!) that have to do the same job as a single Higgs, but make predictions as to the detailed properties of the lightest Higgs-like particle. However, whatever it is has to talk to the W and Z (it's intimately related to their masses, after all), and has to talk to the fermions (same reason). So, to some degree, the LHC has to find something. There is a no-lose "theorem" (really: calculation) which says that, based on the known properties of the W and Z, whatever is responsible for EWSB has to become apparently at an energy low enough to be visible at the LHC after enough data has been gathered.

So, we look for the Higgs not because we don't know that there's something there; there has to be something, or else many of our fundamental building blocks of quantum field theory are just wrong (which is possible, and interesting, but they've proven themselves several times already, so it's unlikely), but because we don't know the full details of what exactly is going on. The simplest answer is just that we'll find the simplest "Standard Model" Higgs, and go from there. The more exciting answer is that what we find in 2.5 hours doesn't have quite the properties we expected, which means that there's more we didn't know about that's related to all of this symmetry breaking and mass generation.

Oh yeah, without the Higgs, the electrons (and quarks) would be massless. Meaning that they would be moving at the speed of light and would be unable to be bound into atomic orbitals. So your atoms would lose all their electrons, chemistry would cease, and the Universe would be much more boring. Hurray for the Higgs.
posted by physicsmatt at 9:53 PM on July 3, 2012 [163 favorites]


Wow. Turns out that it's really hard to explain the Higgs mechanism without the equivalent of a whole lecture series. I'm sure I lost absolutely everyone there, so, um, you all ready for the quiz?

Also, what's the record for the longest comment in Metafilter? Is there a prize I can win if I break it?

Also also, from what I can tell from my facebook posts, there is some serious drinking going on in line at CERN. Which started 9 hours before the scheduled talk time. There is also a fire alarm going off. Which everyone seems to be ignoring, because, hey, it's the Higgs.
posted by physicsmatt at 10:02 PM on July 3, 2012 [8 favorites]


Ok I don't understand Higgs boson at all now.

:(


Or, stated more positively, I now know enough about the Higgs boson to be certain that I don't understand it all. AT ALL!
posted by mazola at 10:11 PM on July 3, 2012 [3 favorites]


Well, that wasn't my goal. So if you want to ask questions, go for it.
posted by physicsmatt at 10:22 PM on July 3, 2012


I have a question: It seems likely now what we're going to hear is that they found the Higgs Boson particle. Which, okay, good work physics! But then what else could they possibly say about it and what would those things mean for physics? From my (very basic, small words!) reading today it seems they could say that they found it and it's here and yeah, there it is and it looks pretty stable and yep. And that confirms the Standard Model but doesn't really open up anything really new? Or they could say they found it and it's totally like a drunk guy at a party and you just never know what it's going to do next and that confirms the Standard Model but also gives hope and direction and, you know, stuff of some kind to various groups of physicists who have Big Other Ideas that possibly people might have thought were kind of ... less standardish? Supersymmetry?

Basically, physicists everywhere are drunk already because YAY BIG PHYSICS DAY! but what's going to make them go WHOA! and sober up and get back to their whiteboards asap? Anything?
posted by marylynn at 10:37 PM on July 3, 2012


After I hear a long physics explanation I imagine turning to The Doctor who has been nodding off in the corner. "So, is that what the Higgs is, Doctor?"

"Well no, it's nothing like that at all. Sort of...No. But if it helps, yes."
posted by ceribus peribus at 10:51 PM on July 3, 2012 [4 favorites]


marylynn, well, some of us are drunk. Others of us are sober and waiting to see certain results in the talk today, so we can finish some papers. Some of us are both drunk AND waiting to see those results so we can finish some papers.

The most obvious thing we are looking for is the rates in certain channels (and by we, I mean theorists for the most part). If you followed that tome I wrote above, the higgs needs to decay into W and Z bosons, with rates that are very tightly fixed by the structure of the electroweak gauge group. So, we'll expect to see certain events consistent with that rate.

However, if can also decay into other things, and those rates could easily be changed by new physics. For example, the Higgs doesn't directly couple to two photons, but it does couple to charged particles (the fermions), that do. So there are induced decays into two photons, which are very rare, but very sensitive to anything that's charged and also coupled to the Higgs. One dominate contribution to these decays comes from the higgs turning into a loop of top quarks, which allows decays into 2 photons. If supersymmetry exists, and the top squark partner (the stop) is light, then those particles will contribute to the loop as well, and we might see a deviation for some of these rates while others are unchanged.

However, even if they have over 5 sigma discovery, there will be huge error bars on all these individual channels, and it might not be clear whether we're seeing real new physics or just statistical noise. Also, there are systematic issues that could come up, which could artificially boost or suppress certain rates.

But that's one thing we'll be looking for
posted by physicsmatt at 10:53 PM on July 3, 2012 [1 favorite]


...and that would be discovery from CMS. Great day.
posted by physicsmatt at 12:43 AM on July 4, 2012 [1 favorite]


This is my favorite of the liveblogs. "Seriously, graphs."

But here's the payoff:“We have observed a new boson with a mass of 125.3 +/- 0.6 GeV at 4.9sigma significance.”

Congratulations, physicists!
posted by gingerest at 12:51 AM on July 4, 2012


CMS: 125.3 +- 0.6 GeV Boson at 4.9 sigma significance.
posted by dirigibleman at 12:52 AM on July 4, 2012 [1 favorite]


Oh man. The ATLAS presentation is in Comic Sans.
posted by dephlogisticated at 12:55 AM on July 4, 2012


God bless physicists, you all just made me feel like the dumbest person alive but... Comic Sans? SRSLY?
posted by marylynn at 12:57 AM on July 4, 2012


Comic Sans is how you present some motherfucking science. That is totally baller.
posted by Mikey-San at 1:07 AM on July 4, 2012 [10 favorites]


Fabiola doesn't give a shit about your typeface elistism.
posted by no regrets, coyote at 1:09 AM on July 4, 2012 [1 favorite]


To be fair, I bet she hasn't slept since Sunday.
posted by dirigibleman at 1:11 AM on July 4, 2012


and 5 from ATLAS, with fewer channels. Awesome all over again.
posted by physicsmatt at 1:37 AM on July 4, 2012 [2 favorites]


physicsmatt: That was seriously the best explanation of the Higgs I've ever seen. It's not an insufficiently satisfying cartoon, and it's not riddled with incomprehensible detail. Fantastic.
posted by edd at 1:47 AM on July 4, 2012


OK, it's 4 am, they are wrapping up. I'm out. See you tomorrow.
posted by physicsmatt at 1:55 AM on July 4, 2012


FWIW, the guy who just spoke (on the right) is Peter Higgs.
posted by dirigibleman at 1:58 AM on July 4, 2012


http://havewefoundthehiggsbosonyet.org/ has been updated.
posted by Mezentian at 3:09 AM on July 4, 2012 [1 favorite]


Okay, if I have this right, the Higgs-Boson is an energy field ... it surrounds us and penetrates us; it binds the galaxy together?

From today onwards, as the God Particle is my witness, Comic Sans is hip again!
posted by Mezentian at 3:20 AM on July 4, 2012


Oh my god. It's a great day for science. I don't understand anything, but boy, am I happy to be alive (and uncharacteristically awake at 6am ET) to hear this news.
posted by tickingclock at 3:58 AM on July 4, 2012


Summing up, we've confirmed to five sigmas probability the existence of another turtle!
posted by seanmpuckett at 4:19 AM on July 4, 2012 [2 favorites]


Comic Sans was never unhip. The people who hate it aren't exactly the social trendsetters at parties. :)
posted by Malor at 4:23 AM on July 4, 2012


Anyone have a link or explanation suitable for a layperson explaining why and how things in a field are connected and interacting at all?
posted by ignignokt at 8:58 AM on July 4, 2012


http://havewefoundthehiggsbosonyet.org has been updated.

By Mefi's own alby.
posted by alby at 10:56 AM on July 4, 2012


Is it accurate to say they've fully confirmed the Higgs boson? I thought that, specifically they confirmed a boson that is probably Higgs but they still need to do more confirmation to get it to the full confidence level.
posted by delmoi at 11:04 AM on July 4, 2012


delmoi: no. they confirmed the existence of a spin-0 particle at 125-126 GeV with decay modes to ZZ and gamma gamma, as well as to b b and WW with lower significance (tau tau is consistent with zero, it seems) that are not quite within the expected rates of the Standard Model Higgs. They are not far off though, and this could be either statistical fluctuation or systematic effects (or real new physics, beyond the SM Higgs). The production modes are also broadly consistent with the SM Higgs.

So, more generally, I think it's fair to say they found *A* Higgs (though that is jumping the gun a little bit). Whether it is the SM Higgs is still to be determined. I hope it isn't, because that would be more fun.
posted by physicsmatt at 11:15 AM on July 4, 2012


Yeah so I'm wondering if it's appropriate to put "YES" on the "havewefoundthehiggsbosonyet.org" website. Doesn't seem to be the case.
posted by delmoi at 3:20 PM on July 4, 2012


Ok I don't understand Higgs boson at all now. :(
Or, stated more positively, I now know enough about the Higgs boson to be certain that I don't understand it all. AT ALL!

posted by mazola at 2:41 PM on July 4 [2 favorites +] [!]

Well, that wasn't my goal. So if you want to ask questions, go for it.
posted by physicsmatt at 2:52 PM on July 4 [+] [!]

This exchange has been making me a little sad ever since it happened. I just wanted to say, physicsmatt, that it's not your fault that particle physics is hard to understand, especially without pictures or equations. Moreover, I'm sure mazola didn't mean your explanation was bad - quite the contrary, I think: sometimes the most a good solid explanation can achieve is to confirm that one simply doesn't have the requisite theoretical background to put the information into context.
posted by gingerest at 3:52 PM on July 4, 2012 [2 favorites]


I'm assuming that if particle physics was easy to understand, we wouldn't be here because the Universe wouldn't have enough turtles to make things interesting.
posted by palidor at 4:39 PM on July 4, 2012


I'll confirm gingerest's theory.

Mine was a stupid reply to a thoughtful post and I apologize for it.
posted by mazola at 4:57 PM on July 4, 2012


No worries you guys, I was mostly trying to make sure mazola and other understood that if they wanted to know more they should ask, as sometimes people get scared off if they don't get the first explanation.
posted by physicsmatt at 7:15 PM on July 4, 2012 [1 favorite]


A lot of great comments here, but so far there is still one unanswered question. How many theoretical physicists are now just run-of-the-mill particle physicists?
posted by TedW at 7:22 PM on July 4, 2012


Here's one question, Although I don't know how easy it is to answer: How does a particle get energy (and therefore mass) by interacting with a field? Is it something as basic as, well, when you do the math, you get energy out of the equation after applying the higgs field to a W boson? (where mathematically these are represented as... matrices?) But when you do the same thing with a photon, you get a zero value for mass, because of the way they interact?

Do people understand the underlying mechanism by which the Higgs field would create "mass" in bosons that interact with it?

The other question is: what's the difference between the Higgs feild and the Higgs boson?
posted by delmoi at 8:46 PM on July 4, 2012


Does this help answer anything?

In quantum field theory the fundamental entities are not particles but fields, like the electromagnetic field. There are solutions of the equations of quantum field theory that represent quantised oscillations of these fields. These oscillations represent particles. The oscillations in the electromagnetic field are the photons; those in the Higgs field are called Higgs bosons.
posted by palidor at 9:05 PM on July 4, 2012


I didn't read your comment in full yet, physicsmatt, but thank you for the clarification about the Higgs boson giving mass to a particular set of particles instead of to everything. That part has had me confused, and my world looks vaguely more harmonious now :).

(I'm surprised, frankly, that that aspect tends to not have been reported more clearly in what I've come across!)
posted by Anything at 11:42 PM on July 4, 2012


Or is there something I'm missing? For example the Wikipedia page on the Higgs boson says this:

'The Higgs boson is a hypothetical particle, a boson, that is the quantum of the Higgs field. The field and the particle provide a testable hypothesis for the origin of mass in elementary particles.'

No qualification of only applying to some elementary particles. Same goes for the Higgs field and Higgs mechanism articles. And pretty much every news article :/
posted by Anything at 12:30 AM on July 5, 2012


Not to say that the more detailed descriptions on the Wikipedia pages don't correct that, but the opening summary seems inaccurate to me, assuming I understood correctly.
posted by Anything at 12:33 AM on July 5, 2012


I think the important thing is that the Higgs explains why 'stuff' exists instead of a bunch of particles wizzing around at light speed.

I guess the next frontier, now that the SM is more or less complete, is to figure out why the various fields exist.
posted by empath at 6:10 AM on July 5, 2012


The Higgs gives mass to the W and Z bosons, the electron, muon, and tau charged leptons, and all the quarks. Those are all fundamental particles as far as we know. The neutrinos are massive (though much lighter than the rest of the fermions), but we do not yet know if they get their mass in the same way as the others. It is likely though that if the Higgs vev was zero, the neutrinos would be massless.

Non-fundamental fermions formed by quarks, like the proton and neutron, would be massive without the Higgs around. The pi mesons made of a quark and an anti-quark would actually be massless, because of a symmetry which makes their mass proportional to the mass of their quarks. Many additional hypothesized particles, such as the axion or supersymmetric particles, do not gain their mass through the Higgs.

So yeah, the fundamental particles we know about mostly get their mass through the Higgs. However, most of your mass comes from protons and neutrons, which are massive because of the strong interaction. That part gets lost a lot in the popular press, which is really too bad.

In quantum field theory, each particle is associated with a field. As there are many particles, there are many fields. Each field can be thought of as set of numbers at each point in space. For a scalar field, like the Higgs, it's just one or two numbers (depending on whether field can be represented by real or complex numbers, which relates to whether the field can be its own antiparticle, among other things). Higher spin fields have more numbers specifying their properties at each point in space.

The important thing about each field is how it interacts with itself and the fields around it. Self-interactions means that, if you raise the field values in one place, the field nearby is perturbed. So you can get waves in the field, just as you can get waves on a sheet, or water, or whatever. These perturbations carry energy, and so gravity (which is its own field, as is everything), affects the motion of the perturbations.

Interactions with other fields means that, as a field perturbation moves around, there is some chance, under certain circumstances that depend on the various properties of the fields in question (e.g perturbations of the gluon field don't affect photons). This translates to particles of one type of field (more on that in a moment) scattering with or turning into, particles of other types of fields. For example, one of the properties of the photon field is that, if you take an excitation of a field that has electric charge (such as an electron), and wiggle it back and forth, some of that energy will be translated into the photon field, causing the emission of photons.

Every field has particles associated with them. This is a quantum effect: you find that these fields can only have a "minimum" excitation, that is localized in either space or momentum (and due to the uncertainly principle, if you are localized in one, you aren't in the other). For a given field, these excitations have many properties that are identical; for example, if a field has a "mass term," then each excitation has to have at least E = mc^2 of energy, and obeys a relation where E^2 - momentum^2 = mass^2. Thus we can call the "mass term" just "the mass," since these properties are exactly what we mean when we say something has mass.

So, the Higgs PARTICLE is what you get when you dump enough energy into a small region of the Higgs FIELD. The background field has some non-zero value (the vacuum expectation value, the having of which makes the Higgs field special), and perturbations away from that are seen as particles. By studying the properties of the particle, we learn about the field (and vice versa, since we know that the Higgs field has a vev, and does all these things to electroweak symmetry, we know that the particle has some specific properties at least).

As for the question of how this really all works, I don't know the answer really. I know the mathematics, and I have a picture in my head of simplified versions of the fields, but whether this is just a useful abstraction or "how the world really is" is not something I can fully answer. Clearly, it's a very useful metaphor and mathematical model, but I don't know if it's the baseline from which the Universe is built, or just an abstraction. You ask "how do these fields interact," and you might be asking "how do they touch" or something similar. But it's more likely that the fundamental thing that happens in the Universe is "fields interact" and the real mystery is "how do things like use think we're 'touching' objects, when it's really just fields interacting?"

I'm back at work now, and the crazy fun Higgs festival is still rolling through the lab (this is our job, after all). I have a lot of Higgs-related work to do, so no more posts here from me during working hours today; I'll try to catch up later tonight if there are more questions I can answer.
posted by physicsmatt at 7:55 AM on July 5, 2012 [5 favorites]


SSsooooooo these fields in 3 dimensional space, they have numbers that characterize their intensity at each particular point in space, is what you said.

Now my understaaaanding is that the smallest distance of relevance in our universe is the Planck length.

So theennnn fields can actually be represented as a three dimensional array of numbers that indicate the field strength at intervals of the Planck length.

Which meaaaaans that you only need a finite amount of data to represent completely a finite amount of the real universe. It's a lot of data. But it's finite. Am I missing something?

Ssssooooo that'd be the red pill, then. the red pill then.
posted by seanmpuckett at 8:46 AM on July 5, 2012 [1 favorite]


In other news: Dark matter’s tendrils revealed: Direct measurement of a dark-matter ‘filament’ confirms its existence in a galaxy supercluster.
posted by homunculus at 10:16 AM on July 5, 2012


It's no coincidence that Higgs Boson looks like a pile of dry spaghetti
posted by homunculus at 10:25 AM on July 5, 2012


seanmpuckett, that's exactly right.

Actually, it's worse than you think. What you are counting is the entropy of some volume, and noticing that there should be a finite amount of entropy you need to specify everything that could happen in some region of space.

In fact, you can show that the maximum entropy in some volume is always less than the volume of an equivalently big black hole. Which sort of makes sense: if you throw enough matter into a volume (which is required to have many field excitations and thus high entropy), you get too much energy to avoid creating a black hole, so that's your upper bound. Now, the amount of entropy of a black hole is immensely more than the entropy content of anything we're used to, so that's not a particularly constraining result. The wikipedia servers are in no danger of violating the black hole entropy bound, for example.

However, one of the things Hawking did was demonstrate that the entropy of a black hole is proportional to its surface area (in particular, it's the surface area in units of the squared Planck length over 4). So, this means that the maximum entropy of any volume is set by the surface area of that volume. To see why this is a huge problem, imagine what happens if you double the dimensions of your room (say it's 20 feet by 20 feet by 20, instead of 10 x 10 x 10, for instance), then you increase the volume by a factor of 8, but the surface area goes up by only a factor of 4. This means that even though you have way more volume, and so way more places for quantum fields to fluctuate and particles to be, so you'd EXPECT way more possible ways for them to be arranged (entropy), in fact you get only a little more entropy to play with (i.e., not enough to account for all the states you thought you'd have). As you extend this to bigger and bigger volumes, the problem just gets more severe: you can't have as many quantum states in a volume as you'd expect, and nothing in quantum field theory (or our normal classical intuition) prepares us for this. It's almost as if there's one *fewer* spatial dimensions around than we think there is.

This is the holographic principle, and what it essentially means is that everything that CAN occur in any volume can be encoded by physics on the boundary of that volume. So I should be able to tell everything that can happen in a room just by looking at the walls, somehow. Since it comes from black hole physics, it has something to do with gravity, and so it's not too much of a surprise that quantum mechanics fails us here. The two theories famously don't play well together. But honestly, this is one of the craziest things I've found in physics, and I have no idea how it can be true. But, as far as I can tell, it is.

Fun, isn't it?
posted by physicsmatt at 6:35 PM on July 5, 2012 [9 favorites]


Without the Higgs, your body would be only about 1% lighter. You would not notice however, since you'd be busy dissolving into ions as every electron zipped off at the speed of light.

So the Ghostbuster's packs must do something with the Higgs-Boson then. Or at least they do if you cross the streams.

Oddly enough, Physicsmatt, I think your explanations make MORE sense with some math in them. I didn't get lost as fast with that last one.
posted by VTX at 10:28 AM on July 6, 2012


We were this close to having a conversation about the LHC without bringing up black holes, physicsmatt.
posted by fantabulous timewaster at 11:37 PM on July 7, 2012 [1 favorite]


Do I understand this correctly -- is it the case that whenever a particle interacts with the Higgs field, this will always involve a Higgs boson close by at some point? Is it at least moderately correct to say that the massive fundamental particles gain their mass through interaction with Higgs bosons or does the field also do things without going so far as to bother with a particle?

Further, is there any mass at all that doesn't come about by the interactions between particles? It was asked sort of jokingly above but does the Higgs boson also get its mass only from such interactions? A moment ago I still thought that mass was something that a particle can just have on its own, but now I'm getting the impression that maybe it's not so?

Also, then, when we're talking about massive things attracting massive things via gravity, are we really talking about 'things that are interacting with each other attracting other things that are interacting with each other'? This just seems bizarre.
posted by Anything at 11:04 AM on July 8, 2012


How Budget Cuts Could Prevent Scientific Breakthroughs: America has been the world leader in scientific research for decades, but we risk falling behind if we don't continue to fund groundbreaking projects.
posted by homunculus at 12:34 PM on July 8, 2012 [1 favorite]


Anything,

If a particle can interact with the Higgs field, it can interact with the Higgs boson. That isn't to say that the Higgs boson is always secretly interacting with a particle getting mass via the background Higgs field, in most circumstances there isn't enough energy around to create a Higgs boson, so the particles around us today (like electrons and up and down quarks) just see the smooth background field. However, it is a necessary consequence that IF you interact with the field THEN you interact with the excitation as well: the Higgs boson.

That's how we knew what to look for in the LHC: we knew that the W and Z bosons get mass through an interaction with a field with certain properties, and the fermions also did; therefore, the resulting particle must interact with the W, Z, and fermions in specific ways. We could have been wrong in many ways about that idea, but (at least to 1st order) we now know we weren't.

So the Higgs field is not the only way particles could gain mass in quantum field theory; and many non-fundemental particles don't gain mass through the Higgs (as I've said above, the proton and neutron get over 99% of their mass through QCD interactions). In fact, from a pure theory perspective, you have to work fairly hard to get particles that need to gain their mass through something as baroque as the Higgs. Your average simple example of a particle just allows a "mass term" without anything so extraneous as an extra field that obtains a vacuum expectation value and so on and so forth (this statement is true for scalars and fermions, not gauge bosons. The fact that the W and Z had to be massive was the key observation that told us something more complicated was going on). It's bizarre that the universe "chose" to have fermions with different charges for the left- and right-handed components, requiring all this mess to give them mass. I don't know why it is that way, and it's fascinating that it did.

The Higgs gets a mass through a self-interaction, but this is different than the kind of interactions the Higgs has with the other particles to give them mass. The Higgs boson would still have a mass even if the Higgs field did not have an expectation value, but the rest of the particles would not.

One way to think about mass is "the price you pay to exist." An electron has a mass of 511 KeV (due to interactions with the Higgs). That means you have to pay 511 KeV to energy to create an electron, or if you manage to destroy one, you get that much energy back. Some particles just have the sort of self-interaction which makes it necessary to pay a price to have an excitation we think of as a particle: the Higgs is one such particle.

Most of the particles we happen to have in our Universe wouldn't require any energy to exist (just kinetic energy, and that can be arbitrarily small), but due to the Higgs field, they now "get a mass." Many composite particles feel the strong force, and get a mass term that way. In this case it's because to have 3 quarks next to each other, you need to pay a huge amount of extra energy to create a cloud of gluons around them. This costs energy, so to exist, a proton needs about 1 GeV's worth of energy.

It may be that we discover new particles at the LHC. Some of these particles could gain mass through the Higgs mechanism, some could not. Even more confusingly, some could gain some of their mass through the Higgs, and the rest through self-interaction mass terms. We won't know till we find them.

You should divorce a bit in your mind gravity and mass. Gravity cares about energy, not mass. Now, since mass is one form of energy, that means things that have mass also get pulled around by gravity. However, massless particles like the photon are also deflected by gravity, and that's because they have energy in the form of kinetic energy, not just mass. Specifically, gravity interacts with the "stress-energy tensor" which includes energy, but also things like pressure and sheer.

So don't think about massive particles and gravity as "this particle interacts with the Higgs and somehow that tells gravity to interact with it as well and then that interacts with that other massive thing over there and oh my god what the hell?" The logic goes: this particle interacts with the Higgs field. As a result, it has to have a certain minimum amount of energy just to exist (it can have more, from kinetic energy). Due to the presence of energy, the gravitational field will be deformed. Any other form of energy happening past will be deflected by that deformation. That energy could be in the form of mass due to a particle interacting with the Higgs field, or it could be some other form of mass/energy.
posted by physicsmatt at 2:42 PM on July 8, 2012 [7 favorites]


Pakistan shuns physicist linked to Higgs boson
posted by homunculus at 4:59 PM on July 9, 2012


Okay, so now that I know that space is a matrix of numbers, here's where I'm thinking next.... how could use that matrix in a simulation?

If one divides the speed of light by the Planck length, that's the Planck time, which is 5.391  × 10−44 seconds (according to wiki). That's the amount of time it takes information to propagate from one "matrix cell" of the universe to another.

So with a defined minimum granularity to both time and space, one knows not only how much information one needs to represent a defined section of space in a moment of time, one also knows how often one must process that information to get to the next moment, which is 5.391x10-44 seconds later.

And that means the universe could absolutely be simulated 100% realistically by an iterative process that takes one moment, crunches the numbers in the Planck matrix, and the result is what happens one Planck moment later. Do this over and over, and one gets a universe just like ours.

All of this is kind of freaky, at least I am kind of freaked, that there is no such thing as an infinitely small thing, or an infinitely short amount of time. There's a minimum distance that matters, and a minimum amount of time that matters. Infinity may go all the way up (in that we will never know for sure what is outside our light cone), but it sure as hell doesn't go all the way down.

I am also amused that the "Tomorrow People" teleported by slipping between one instant and the next. Sounds like made up fiction crap but if one establishes that time is actually made up of discrete intervals, it holds together -- one would teleport by simply by moving the relevant numbers in the matrix during the calculation phase.

So, my next question is this: how many values does each cell in the matrix contain? (And would these be the additional dimensions over 3 that physicists talk about?)
posted by seanmpuckett at 6:10 AM on July 10, 2012


That's Steven wolfram's idea.
posted by empath at 7:11 AM on July 10, 2012


seanmpuckett, your matrix would imply a preferred "at rest" reference frame. Observers boosted to high speed relative to your matrix would see your cells as having less than the Planck volume (due to length contraction) and your time step as longer than the Planck time (due to time dilation). This breaks the principle of relativity, the principle that there's no preferred reference frame, which is the justification behind the theory that leads people to talk about the Planck scale in the first place.

The various combinations of G, ℏ, and c that give rise to the Planck length, time, mass, and energy are indicative of where we might expect relativity and quantum mechanics to become important at the same time, simply because when you do algebra with some theory you tend to get the dimensionful constants of that theory multiplied by numbers not much different from one --- as in expressions like energy = (1/2) mv2, or volume = (4π/3) radius3. But that's all they are: indicative. Anyone who claims to know what happens near the Planck scale has a book to sell.

but what a totally fun idea! and it's so similar to lattice QCD, which is a hot topic and money fountain in these days of parallel computing! and the volume of a proton is only 1060 Planck volumes ... hmmm, wait.

Sorry to be a spoilsport.

posted by fantabulous timewaster at 10:02 AM on July 10, 2012


Here's What the Higgs Boson Sounds Like: The particle, set to music, plays like a jaunty tango.
posted by homunculus at 10:09 PM on July 10, 2012


seanmpuckett, yeah, I think there's definitely some use in thinking of the Universe as a pixellated computer; I did a little work as an undergraduate with a professor who was thinking about a quantum Game of Life. (around the time that Wolfram's book came out. The less I say about that guy, the better), so its definitely something that information theorists take seriously.

That said, I don't think its necessarily the end-all-be-all that it might appear to be. For one thing, the holographic principle I described above implies that there's some non-trivial correlation between "pixels" that we don't quite understand. fantabulous timewaster's point about relativity is also a good one; though possibility there's a Lorentz invariant way of constructing all this. I haven't thought in detail about it in a while. (Relatedly, one of the problems I have with my description of Higgs physics here is that it makes things sound like there exists a preferred frame in the Universe. That's a failure of the analogies I'm using: the physics itself is appropriately boost-invariant.) Basically, as a guy who does particle physics, I don't think we understand the fundamental structure of the Universe well enough yet, but hopefully that will change in the future, in which case, its possible that this is the best way to think about how the Universe evolves from one state to another.

As for the extra dimensions, I wrote a post about them on an older thread here at Metafilter. The way to think about them in this context is not as a place to store the information about each point in space, but as extra values that would have to be assigned to each field at each point in space. One of the sets of values you'd have to specify for each field at a point would be the momentum in 3-space (and energy, which is basically momentum in time). The extra dimensions are saying that, if you have enough energy localized, you now have to specify more momentum numbers for these other directions. Since they're compact, we get to ignore them at our scales, which is just another way of saying "everything with low energy gets the same set of numbers in those other directions, so we can ignore them."
posted by physicsmatt at 7:58 AM on July 11, 2012 [1 favorite]


So I was thinking the other day about a shuffling algorithm and entropy, and ... does an equation explaining the entropy of a system (sorry, while I try to understand this via things like Brian Greene's book, entropy throws me for a loop at times, so I'm not sure if my terminology is correct)...

Does the entropy of a system include the descriptor of that system? That is is there a difference between the system and the equation? Do equations have entropy? Can they change (I guess that's what calculus and differential equations are?) Is there a sort of meta-entropy?

Is this even making any sense?
posted by symbioid at 11:15 AM on July 11, 2012


Symboid: entropy can be thought of as the number of micro-states in a particular macro-state. When you're dealing with strings of binary numbers you use the formula -Σp(xi) * log2(p(xi)) where each xi represents the probability of that micro-state. (Remember the log of a number between 0 and 1 is negative)

In theory, everything should be able to represented as a string of binary numbers (every finite quantity, anyway). So the probability of an individual micro-state would be 1/n where n is the number of bits. So you would use that number, 'n', in the equation. But entropy is a function of the underlying information. It doesn't "contain" the original variables that were used to calculate it. If you have an entropy of exactly 82.9342, there are probably a number of possible combinations of descriptor length and probability that could give you that result.

Just like if you're calculating how high a ball will go if you throw it using physics, the result is derived from the speed you throw it and strength of gravity, but the result doesn't really 'contain' those quantities, there is would be a bunch of different possible speed/gravity combinations that give the same result.
Which meaaaaans that you only need a finite amount of data to represent completely a finite amount of the real universe. It's a lot of data. But it's finite. Am I missing something?
Yeah and like other people said they actually know how much data is needed to store that information: never more then the surface area divided by the plank length (divided by 4, apparently). That's the Holographic Principle, and the information in a black hole is exactly the same as the surface area of it's event horizon. Pretty crazy, right?

Going back to the binary string thing, you can think of any non-black hole region of space as being kind of like a binary string with "a lot of zeros" while a black hole would be kind of like a binary string with an equal number of ones and zeros, which would have the maximum possible entropy.

So the idea of the universe being a 3d matrix of cubes doesn't work because of relativity, but one question is whether or not it could be a 2d matrix on the surface of a black hole (or something like that). That's what I think people are talking about when talk about the idea of the universe being a hologram on the surface of a black hole (again, I haven't ever seen the math explaining that idea, so it's just a guess based on descriptions I've heard of it)
posted by delmoi at 3:29 AM on July 13, 2012


A 2d hologrammatic matrix representation could address non-locality issues that are also a problem with a 3d representation.

I think my biggest problem is that none of it makes any sense at all. There's no "why" there's just "how", and the how is incomplete. And as a person who loves to know why, theoretical physics is maddeningly unfulfilling. I suppose I could walk up to the Perimeter Institute and stand on the floor of the atrium and shout up to the balconies WHY WHY WHY WHY WHY like a mad person, and a whole bunch of geniuses would come out and try and soothe me. Or more likely shoo me out.
posted by seanmpuckett at 7:25 AM on July 13, 2012


Video from UCBerkeley TV with Lawrence Hall and Beate Heinemann and others explaining the new results from the Large Hadron Collider. (Skip to ~ 10 min if you don't want the front frou-frou. There is also some final frou-frou for five minutes or so.)
posted by bukvich at 9:11 AM on July 25, 2012


BBC: Higgs boson results from LHC 'get even stronger'
posted by the man of twists and turns at 10:09 AM on August 1, 2012 [1 favorite]


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