Physicists Say They Have Found A Higgs Boson
nytimes.com
nytimes.com
"It remains an open question, however, whether this is the Higgs boson of the Standard Model of particle physics, or possibly the lightest of several bosons predicted in some theories that go beyond the Standard Model. Finding the answer to this question will take time."
I find this to be a pretty important distinguishing factor. Not only will it take a while before they really do know, but it may not, in fact, be the Higgs so many have been searching for to fit into the Standard Model.
Many news sources are already claiming that the "god particle" has been found.
[0] - http://press.web.cern.ch/press-releases/2013/03/new-results-...
The first question, "is the Higgs mechanism how elementary particles get their mass?" is now essentially answered. Whether or not the Higgs boson is a single particle or part of a hierarchy of related bosons is almost irrelevant to the answer of this question.
The second question is "is there new physics at the TeV scale?" If there is, then there are additional bosons related to the Higgs in some models like supersymmetry. However, it is not required that there be additional bosons or that that they be easily measured. Other new particles might be more accessible. On the other hand, there might not be any new physics at LHC energies at all. This question is what will take time to answer.
God Particle Found! News at eleventy eleven!eleventy!
When I was a bartender, I would often consume tidbits of popular sporting events or news just so I could hold conversations with my patrons. I had absolutely 0 interest in who crashed at Daytona that day.
In my experience most people don't form their opinions based on the totality of current knowledge and keep adjusting them in some Bayesian fashion as more info becomes known. Rather they make up their minds based on something (could be their knowledge of currently accepted facts, could be what they were taught growing up, could be just what they think makes sense, etc..) and then simply scan for confirmatory data, or simply don't pay any attention because they already have it 'figured out'.
Thus if you already believe in god and heard that scientists had discovered the 'god particle' you would likely say 'see, I knew it!', if you didn't believe in god and saw the same thing you would say 'I am skeptical, let me read this article', and you would walk away saying 'that is just a name, it has nothing to do with god, who still doesn't exist'. So really I guess both sides win, and we all lose, or maybe I am just too cynical.
The uncertainty is about the structure that exists beyond the standard model. Some sort of Higgs is still necessary in almost any extension to this model, which is why everyone was so damn certain it would be found.
My understanding from the statement is that they know there is the effects of a Higgs has been observed. But that this isn't necessarily the Higgs which fits into the Standard Model. I understand there are other models which may be considered but I thought that there were specific conditions which would satisfy the Standard Model.
We know that the standard model is "wrong" -- it breaks down at high enough energies. But it's valid at lower energies; it works for the stuff we can actually observe. And it requires a Higgs field to make sense.
If they discover a particle that fills this role, that's discovering "the" Higgs. It doesn't matter if it turns out that the Higgs sector is more complicated; the fundamental prediction of the standard model has been vindicated. Even though everyone kind of expected this, its still a big deal!
So if a pop science article says that the Higgs has been discovered, they're not really being sensationalist in their wording. Working physicists would say the same thing.
(They might be a bit off in pointing to this particular announcement as the discovery, of course! The bbc seems to have the most sober coverage of this sort of thing: http://www.bbc.co.uk/news/science-environment-21785205)
Now, it's quite likely interesting stuff happens before that point! (Such as the extra Higgs suggested by supersymmetry.) And there are also other, complicated reasons to suspect that the Standard Model breaks down, to suspect that it is really what we call an "effective field theory".
That's all ignoring issues like dark matter or the neutrino mass, which are not predicted by the standard model. But it's kind of interesting that the model (in a certain sense) naturally limits its own predictions.
Sensationalism where?
The organisation of such a vast data-processing task has surely brought about many discoveries in "big-data" and parallel computing that are not directly related to the discoveries in physics. Much like the research into the magnets that power the accelerator has led to new MRI machines. To people who don't see the point in "science for science's sake", this is a massive spin-off of CERN that will hopefully greatly benefit the world.
[1] http://en.wikipedia.org/wiki/History_of_the_World_Wide_Web#1...
Gopher existed before WWW and filled the same niche. It wasn't as elegant, but it (or something else) would have grown up without WWW.
The reason, in my cynical opinion, why the web took over from Gopher was not that it was technically superior, but that it allowed people to add pictures to their documents.
Which very well may be a good definition of technical superiority for the lay man :)
The primary benefits of www over gopher at the time were that the web supported text input (you had to use wais just to search gopher and you couldn't build say, a forum) and html which allowed embedded images and formatting.
1. Gopher was developed at the University of Minnesota, so it comes from academia as well
2. Part of what killed it off was the University trying to make money from it through licensing fees
I find it to be a wonderful feeling.
I've loved watching the tête à tête between the 24-hour news and this extremely important science community. More than once, extraordinary claims have been made and completely overblown by the media. Meanwhile, these talented scientists have remained levelheaded, critical, and extremely careful in their announcements. Watching the FTL[0] discussions, for example, was just so much fun. It actually gave me more faith in humanity to see so many people fact checking each other and challenging each other to prove something in civilized ways.
[0] - http://en.wikipedia.org/wiki/Faster-than-light_neutrino_anom...
Still, I have a similar feeling, that there may be some hidden 'tuning' to make things match, or some assumptions or values that have been erroneously determined or set.
It's enough to say that the standard model has to have some input from the real world -- mostly the masses of the particles and their mixing angles. Renormalization just makes it harder to talk about what a particle's mass "really" is; it doesn't really increase the number of parameters in the theory.
[0] Effectively the basic rate of things happening per particle/energy/volume of spacetime etc., originally assumed to be constant. [1] Effectively things happening faster for certain types of interactions (electromagnetic vs. weak vs. strong).
The design of these detectors are rather different, and they are build by different team, yet are are giving consistent results.
So of course they are common assumptions, but they did do their homework to try to mitigate this.
However, ‘practical’ uses of these physics are not immediately obvious in the way special relativity is necessary to get decent GPS[0]. Nevertheless, both the engineering advances _and_ the mathematical tools invented during such research prove very useful time and time again - methodology from String Theory, for example, is used in trying to find dynamical descriptions of superconductors, which, if found, will affect daily life strongly (hopefully).
The key point to keep in mind here is that predictions about the future are rather hard and we have no idea what weird things people come up with in twenty or thirty years time, let alone a hundred years. Or could you have predicted the global cat picture viewing machine mentioned next door in 1913?
[0] And to understand why more than 3 to 4 GHz are rather impractical if you want to keep the CPU and RAM physically separated, btw.
Someone up there having a joke, obviously.
If psychology adopted this level of scientific discipline, it would destroy the field -- most psychological "discoveries" are based on votes, not experiments: http://arachnoid.com/building_science
However, SOMETHING needs to break electroweak symmetry---this is known because the W and Z gauge bosons are massive, and it isn't possible to formulate a consistent gauge theory with massive bosons without symmetry breaking. Whether it was the Higgs mechanism, or some technicolor (strongly-coupled, QCD-like) theory, or something else entirely was not well constrained before the machine turned on. With that in mind, it's clear that it might be that what they found is not just a standard model Higgs, but one of a number of higher-energy excitations. If that's true then the Standard Model is not, strictly speaking, correct, though it can be thought of as an effective field theory ( http://en.wikipedia.org/wiki/Effective_field_theory ).
No, that's called "proving a negative" -- in most cases it's an impossible evidentiary burden. For example, no one will ever be able to say that Bigfoot doesn't exist for lack of evidence. This is why the null hypothesis is the default scientific precept -- that something without evidence is assumed not to exist (but by no means proven not to exist).
Look carefully at this graph: http://www.quantumdiaries.org/wp-content/uploads/2012/07/Hig...
This graph shows how many pairs of photons were crated, classified by the energy.
There are a lot of ways to create a pair of photons, so there is a lot of background noise even if the Higgs Boson doesn't exist. This is roughly the dotted line (it's very difficult to see, because it's almost covered with the red line).
The black points are the actual measurements. They almost agree with the dotted line, except in the range of 125-130GeV where there is a bump. In that energy range there are more pairs of photons created than the expected quantity. The energy of the photons is essentially equal to the mass of the HB, but there are some dispersion because of the measurements errors and some quantum effects.
The red line is a simulation of how many pairs of photons would appear if the mass of the HB were 126.5GeV. They adjusted that parameter to get the best fit. This red line has a bump near 126.5GeV that is similar to the bump that the measurements have (black dots). The dotted line is very similar, so the red line cover it everywhere except in the bump range.
There is a lot of noise, so one possibility is that the bump is only a lucky streak, so they wait until they get a 5 sigma deviation, i.e. there is only 1/2000000 chance of getting a deviation as big as that form random fluctuations and noise. (The graph is old and shows only a 4.5 sigma deviation.)
The complete analysis is more complicated, but the general idea is that if there were no HB, they would get a different signal.
While it not possible to disprove the existence, of, say, unicorns. It is possible to say "I've searched the length and breadth of Central Park, looking for unicorns with 99.9% detection probability for each square meter of the park. I found no unicorns."
Whether you find this sufficient to reasonably exclude any unicorn hypotheses is up to you and will depend upon whatever unicorn hypothesis you wish to test. If the hypothesis is that the world should be uniformly populated with unicorns once every hundred meters, then the above observation should place strong constraints on the viability of the hypothesis, as about 340 unicorns should have been observed.
In the case of the Higgs, had the signal not popped up, they would have been able to exclude any Higgs-like particle over a huge range, which includes the now-claimed value. At the present mass, with the data up till now, they would have excluded a Standard Higgs to better than 5-sigma (less than a one in a million chance that they missed it).
Want to see the one of the peaks as it forms? (you have to trust that the scientists are doing the analysis right before they make this plot)
https://twiki.cern.ch/twiki/pub/AtlasPublic/HiggsPublicResul...
There was also an attempt to explain what is the Higgs Boson , by means of some drawings and analogies in the second part of the series. Perhaps someone knowledgeable could comment how accurate the explanation is.
[1]http://www.nytimes.com/2013/03/05/science/chasing-the-higgs-...
pt1: http://www.youtube.com/watch?v=9Uh5mTxRQcg
http://www.nobelprize.org/nobel_prizes/peace/laureates/2007/
Too bad -- a science writer wouldn't have made this elementary error.
At what point do we stop giving names to particles? Are we there yet?
In other fields I see a pattern of trying to categorize things into relatively short lists that a human can comprehend. E.g. phonemes for speech. It turns out that phonemes don't work, but by using a much finer-grained classification you get a system that does work.
So for particles, charm quark or top quark are not particularly descriptive. The names are really no better than "excitation 112" and "excitation 236b". Perhaps a bit more memorable, but not more descriptive of the physics.
Could be a good time to pick up some physics PhDs for your data science team.
[1] http://news.discovery.com/space/we-might-not-live-in-a-holog...
Do you mean the Standard Model? Well, to answer, look at the history of scientific theories -- every scientific theory ever put forth has eventually been proven either flat wrong or been shown to be an approximation, without exception.
The Standard Model more or less includes General Relativity, and General Relativity conflicts with quantum theories, so there's already a basis for further work. That work is being addressed by (among other things) string / superstring / M theories, unfortunately without any experimental testable predictions yet.
It's exactly the same as saying that Newton's law of gravity will hold forever. It applies very accurately under most circumstances; situations that require us to deal with the complexities of general relativity are quite rare. (GR only begins to differ from Newton's gravity when you have extremely strong gravity or when you need extremely high precision.)
But if you want to really understand the inner workings of the universe, Newtonian gravity won't cut it: you need GR. And it's pretty well established that the standard model can't be the whole story, either: its mathematics eventually break down when the energies get high enough. So there's got to be something else up there... we just aren't sure what it is.
So does this mean that an ether really does permeate space?
The Higgs field also permeates all objects, but the mathematical structure is different and it has no preferred frame, so there is no truly still object, all the movements are relative.
This is not a strange thing. The photons are the bosons of the electromagnetic field, that also permeates all objects and it has no preferred frame, so there is no truly still object, all the movements are relative.
And the gluons are the bosons of the strong force field with exactly the same properties.
Even the electrons have and associated field that that also permeates all objects and it has no preferred frame, so there is no truly still object, all the movements are relative. But electrons are fermions, no bosons, so some properties are different, but they have an associated field.
The same happens with the up and down quarks (and neutrinos). Each one has a associated field, with the same properties. (And the other particles too, but this is becoming too repetitive.)
The strange thing is not that the Higgs Bosons have an associated field. The strange thing is that the vacuum expectation value of the Higgs Fields is not zero.
In all the other cases (photons, electrons, ...) the vacuum expectation value is zero, so if you have an empty box, there are almost no particles there (some virtual particles appear, but in some sense they are only a few, (in another sense they are a lot, but it's better to think that they are only a few).) The important thing is that if any particle pass through the box, it will almost not bounce against any other particle (photons, electrons, ...) because it is empty.
But for the Higgs fields the vacuum expectation value is not zero! So even inside the empty box the value of the Higgs field is not zero, there is something like a background value. If any particle passes through the box, it will bounce many many many times against the background even if the box is empty. An easy way to interpret all this bouncing is to say that the particle has apparent mass.
But the Higgs field is not even, it has bumps, and those bumps are the Higgs Bosons. The empty box has only very few Higgs Bosons (or a lot in another technical sense). The normal particles can bounce against the background (vacuum expectation value) and we call it "mass" and they can also bounce against the bumps (bosons) and we call it "interactions".
A very important thing is that the Higgs Boson is totally unrelated to the shape and size of the object. It's related only to the mass. (I can even tolerate "weight" with scare quotes in a divulgation article.)
"The cost [...] has been evaluated, taking into account realistic labor prices in different countries. The total cost is X (with a western equivalent value of Y) [where Y>X]
source: LHCb calorimeters : Technical Design Report
ISBN: 9290831693 http://cdsweb.cern.ch/record/494264
"Finding" the Higgs is a prolonged statistical process involving tons of data that need to be crunched and the experiment itself also needs to run for a long time in order to yield this data. Physicists have been talking about a strong signal indicating the existence of the Higgs for quite a while now, so its existence has not really in question for some time. The problem with continuous and statistical analyses then becomes: when do you actually announce you found the damn thing? That's why it has been announced several times (and probably will be a few times more).
But it's real.
It would have been surprising, but way more exciting, if the Higgs didn't exist.