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Neutrinos, Muons and the Standard Model
Posted by
michael
on Fri Nov 09, 2001 04:49 PM
from the lions-and-tigers-and-neutrinos-oh-my dept.
from the lions-and-tigers-and-neutrinos-oh-my dept.
scorp1us writes: "I can't believe I haven't seen this posted yet. Apparently experiments in particle physics aren't holding to theory. The result: a search for a new form of energy or matter. Read about it in the Post. No wonder witches weigh as much as a duck."
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Neutrinos, Muons and the Standard Model
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Your logic escapes me. (Score:3, Funny)
A "high" powered "particle" beam? (Score:5, Funny)
Great. It looks like it's not just the moderators, then.
I'd like to get in a check out Fermilab (Score:2, Offtopic)
Um...yeah? (Score:4, Informative)
I think it was posted yesterday [slashdot.org]. It just didn't reach the front page.
That article had many more references, too...
Always wondered... (Score:1, Troll)
Re:Always wondered... (Score:5, Interesting)
But this is the defining characteristic of science: everything, always, is open to question. Hypotheses that are borne out by experiment and observation turn into theories, and those theories which stand the test of time are honored by being called laws, but none of them are "facts" in the sense that they can't be proven wrong. This is the principle of falsifiability, and it is the one thing which sets science apart from religion, philosophy, law, and other areas of human intellectual endeavor which seek to make statements about our world.
So relativity isn't a "hard fact." Neither is gravity. But that gravity, and relativity, and evolution, and plate tectonics, et bloody cetera, will operate the way the theories say they will, is the way to bet unless and until something dramatically better -- and by "better" I mean "backed by lots of reproducible evidence" -- comes along.
Re:Always wondered... (Score:4, Informative)
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Could you give some examples of what you're talking about? For the record, I work in biotech, and pretty much our whole business is built on falsifiability; I've never heard a working scientist argue seriously against it.
----------
I'll take a stab. Suppose I say "It's raining outside." This sounds like a classicly falsifiable statement. But is it? If you look out the window and don't see rain, it may be that I was wrong. Or (I could perversely argue) it could be that you (incorrectly) assumed that
1) by "outside" I meant "outside, near this building" not "outside, somewhere"
2) the rain would be all around, not just on the side of the building with the window
3) the rain drops would be large enough to see
4) there would be enough rain drops to notice
5) it would still be raining by the time you looked
6) enough photons would interact with enough raindrops before reaching your eyes that you would detect the rain (instead of all missing)
7) the window really is a window, and not a clever high-res display
The hard core rationalist claim that "all it takes is a single counter example to disprove a theory" doesn't really work. In practice, then, we deal with a sort of fuzzy-falsification, and come up with estimates (w. specified confidence levels) that an assertion is true or false. A single test can't really topple a theory since you can't know for sure that the problem was in the theory and not in your test.
Make sense?
-- MarkusQ
Hmmm, if the laws of physics keep changing... (Score:2, Funny)
Seriously though, this is cool stuff, I'd read the actual paper when it gets published but I'm sure I'd drown in a see of evil mathematics.
Changing theories (Score:4, Insightful)
I think that this is maybe not so surprising. Theories in particle physics are very unlike a lot of other theories. There's not much evidence sitting around for some of these things, and as new evidence comes in, the theories change.
This is true for any scientific endeavor, but the changes are much more rapid in things like high-energy physics.
In short, I'm just saying that it shouldn't be taken as a "radical breakthrough" just because someone had the muon equation wrong, because it was going to happen at some point.
More forms of matter? (Score:1)
I thought the guys who won the Nobel Prize for Physics already discovered a new form of matter. Is this more of their findings, or something totally different? Does this mean that there could be 2 new forms of matter to bring the total up to 5 forms?
Plus:
"On a statistical basis, that would be a 1 in 400 probability of happening as a result of chance. "
That doesn't seem like a big deal to me. That sounds more like a problem in the experiement. I don't think anyone should be jumping for joy at this discovery until they duplicate it in another test.
Follow-up experiments. (Score:4, Informative)
That doesn't seem like a big deal to me. That sounds more like a problem in the experiement. I don't think anyone should be jumping for joy at this discovery until they duplicate it in another test.
This *is* a duplicate experiment - or close to it. Check the previous Slashdot article on the subject. This project is measuring a value that was measured by three previous experiments. Two of the previous experiments gave a very wide range for results, and the other one gave a narrow range for the results consistent with this experiment's results.
Re:More forms of matter? (Score:5, Informative)
Totally different. The Nobel guys found a new state of matter, the Bose-Einstein condensate.
There's already (at least) 5 states of matter: solid, gas, liquid, plasma (gas so hot that it gets ionized - the sun's made out of it), and the recently confirmed Bose-Einstein Condensate [colorado.edu] (gas so cold that weird quantum things start to happen).
You've also got the degenerate states of matter found in white dwarfs (where the electrons squeeze together), neutron stars (where the electrons smush into the nucleus), and black holes (where...well, it all breaks down there). These don't seem to be counted in the usual enumeration of states of matter, but then they've never been produced on Earth, they're really still theoretical.
What they'd be looking for out of this new discovery is more along the lines of a new fundamental particle or force.
Deja vu, and not a very good article. (Score:5, Insightful)
http://slashdot.org/article.pl?sid=01/11/08/22212
What the experiment shows is that the plan-vanilla Standard Model doesn't perfectly match reality. This is a surprise to nobody.
The results give a tantalizing look at one region of this breakdown, but proclaiming "a new form of energy or matter" is a bit premature at this point. What this will actually do is help confirm, refute, or fine-tune a few of the new models that are replacement candidates for the Standard Model.
Not Reviewed Yet (Score:5, Informative)
In science, especially physics, there is a tradition of review which has caught many claims such as this before.
It is likely that they have missed some minor force or effect in thier Standard Model calculations, or that we simply need to understand neutrinos better.
Until a Physical Review Journal accepts research, and even sometimes after that, it should not be viewed as anything more than fantasy.
Don't forget the implications... (Score:1)
Peter Meyers, a professor of physics at Princeton University who was not part of the research team, said the finding is the "sort of crack" that "has been sought for many, many years."
I'm sure this will the ultimate crack that crackheads everywhere will be searching for and paying top dollar for.
What should they name it? (Score:2, Funny)
what kind of crack? (Score:1, Redundant)
Peter Meyers, a professor of physics at Princeton University who was not part of the research team, said the finding is the "sort of crack" that "has been sought for many, many years."
More Information (Score:3, Informative)
Blatant Karma Whoring Link (Score:2)
Karma whore disclaimer: This link was stolen from the other article [slashdot.org] about this experiment.
/me applauds. (Score:5, Insightful)
This is what I love about science. Here we have the Standard Model, formed from exhaustively detailed tests over the last 30 years. As the article states, the model is very precise, and slight deviations are significant issues. However, rather than scrap the entire idea, or announce that the tests were probably flawed, or decry the scientists who performed the tests as heathens and radicals, here we see that the community will embrace this new data and reform the model in such a way as to make it work.
This is the beauty of science. If something doesn't work out the way it was supposed to, if a theory doesn't fit with the cold, hard data, the majourity of scientists will go out of their way to fix the theory (not the data). Scientists are always going out of their way to keep each other in check; at any given time one scientist may be checking some prominent theory or another. It keeps them honest, and while the system isn't fool proof, it's damn tight.
Sometimes it's great to be a geek.
~Aaron.
Got 'cher evidence right here. (Score:4, Interesting)
Do a google search on Alfred Wegener, and you'll see a guy who got his ass kicked all over the place for proposing a theory that contradicted scientific understanding at the time. And was harassed as vigorously as any religious heretic. Want more? Here's the frigging link [nasa.gov].
Through the hoop, nothin' but net.
Do yourself a favor and check out Science's reaction to Darwin and doubters of Global Warning. Shocking behaviour all around, if you ask me.
It all seems to be breaking down. (Score:2, Interesting)
I really wonder if we might not be better of throwing the physics textbooks out of the window and starting over again.
Non absolutes... (Score:2)
"...prompting physicists yesterday to announce that they might be on the verge of finding a new form of matter or energy."
"While this discrepancy could be a fluke, then scientists who conducted the experiment said the odds were it represented something meaningfull..."
"If some hidden matter or energy did cause the discrepancy..."
"It could be a very big deal..."
"It would be very exciting if we find another force"
"...there is a high probablility that something is wrong with the theory"
Just something to think about, not really a big deal, but it would be nice for people to just tell it how it is.
Re:Non absolutes... (Score:4, Insightful)
"The wise man is the one who realizes that he knows nothing." - Socrates
So that's why they call 'em High energy physicists (Score:3, Funny)
I am always wary of results obtained by any physicists who have spent years and years seeking any sort of crack.
(Sorry about that)
And thats what really happened.... (Score:1)
There is a simple explanation... (Score:2, Funny)
Anyhow, if the results of all experiments had to agree with theory, undergraduate physics labs would have disproved all the laws of physics a long time ago...
Actually... (Score:2)
Its not that witches weighed as much as a duck... Its just that the duck has a higher dispacement of water pound for pound than your typical witch does.
And yes, PROPAGANDA is still up,
My daughter has the answer! (Score:4, Funny)
My wife and I laughed for about a half hour, since she always steals the croutons from our salads at restaurants.
From Particle Physics (Score:3, Insightful)
Neutrinos only interact with other particles through the electroweak force (ignoring gravity for the moment). There are three bosons which "carry" the electroweak force, called W+, W-, and Z0. The discrepency with the Standard Model seems to occur with the Z0 (called the neutral current in the paper).
There are several things it could be other than a new force. The scientists will have to eliminate all forms of background noise and detector errors, the possibility that it was just some sort of hadron resonance, and a lot of other things.
It is amazing how sensitive particle experiments can be. I remember reading about one that had to filter out (among other things) the noise caused by the motion of the moon orbiting the earth in order to extract the signal.
That said, I think they may be on to something.
Ah, let it flow. (Score:1)
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Neutrinos, they are small.
They have no charge, they have no mass.
They do not interact at all.
The Earth is just a silly ball
to them through which they simply pass
Like photons through a sheet of glass
Or dustmaids down a drafty hall.
They snub the most exquisite gas,
Insult the stallion in his stall,
Cold-shoulder steel and sounding brass
And pass, like tall and painless guillotines,
through you and me into the grass.
At night they enter Nepal
And pierce the lover and his lass
from underneath the bed.
You call it wonderful? I call it crass.
- John Updike
Not rare enough. (Score:2)
I'm sure the Standard Model has endured way more than 400 tests.
A few more labs need to repeat this experiment to make sure the result is accurate.
--Blair
P.S. If a neutrino is chargeless, how do you "fire" one at something?
But who gets the patent? (Score:2, Funny)
.
big deal (Score:1, Redundant)
The article, in essence, doesn't say anything about anything. These kinds of things happen in particle physics every day and it takes more than that to change the established theory.
The established theory? To begin with, the Standard Model only involves massless neutrinos. There are already many 'established' discrepancies to the Standard Model: for instance that neutrinos have non-zero mass, and the Higgs mechanism by which masses are created.
So there's already 'something wrong with the theory'. And everybody knows that. The Standard Model is somewhat an old fart among many, partly contradictory theories in particle physics.
So, I don't have a cool concluding quip today, just the note that this isn't real news.
Neutrinos -- Heavy Man! (Score:1)
Unlike electrons, which are negatively charged, neutrinos have no charge. Because they are also very light compared with other subatomic particles, they behave in a ghostly way...
Correct me if I'm wrong, but I thought we were still working on the whole "Do neutrinos have mass?" question. If something has no mass can it be said to be lighter than something else?
Neutrinos are .... SMALL? (Score:1)
Well, I didn't think it was a matter of size...
The Standard Model and the Linux kernel (Score:2, Interesting)
For example in the begining there has been only
one generation of quarks and leptons.
(namely: up and down) But on electron collision experiments showed that there must be new generations: (now called
strange - charmed and beauty - truth.)
Until 1995, where experimental evidence was found, the truth quark was only a postulate based on symmetry considerations.
The same applies to symmetry conservation. For a long time CP (Charge conjugation with Parity) was considered conserved. But an experiment on T (Time inversion) violation showed if CPT was to be conserved, CP must be violated. Again the standard model had to be adabted.
And at the CERN (Eruopean Nuclear Research Center) in Geneva they believe, that they have fond some evidence for the so called Higgs particle, which is the cause for the mass of particles. A proof for the Higgs particle would be an enhancement for the Standard Model
Those examples show that the Standard Model of Particles and Interactions is not a static one.
It is almost like the linux kernel - if you permit this comparision - people send in patches.
If a patch is useful it will be released for the masses
Maybe we are entering a odd release stage now
Not that significant (Score:2, Insightful)
Re:Not that significant (Score:5, Informative)
As a former experimentalist in the field (they gave me the Phd so I couldn't be all that bad) I am not getting excited.
The problem is that the experiments are simply not accurate enough to jump up and down in celebration for such a miniscule deviation.
What I am really suspicious about is that the number of observations is much lower than expected. That can happen because you just missed some particles you should have seen.
You can have a deviation that is 'significant' at twenty or a hundred standard deviations and it can still be the result of experimental error rather than a flaw in the standard model.
Given the way the physicists write their programs I would not be at all surprised if this turns out to be no more than the result of a flaw in PAW or GEANT. A physicist will go off to beg congress for a billion dollars to four experiments on the same accelerator (e.g. LEP) so that each can cross check the results of the other. Then they will all share the same analysis programs even though they are known to be riddled with bugs. And don't start on about the Web, first off the Web code was not built on a twenty year old code base from the dawn of Fortran, second there were multiple versions of the code written from the very start. In 1992 there were 10 browsers and at least 5 Web servers.
what have they been smoking? (Score:3, Funny)
"Peter Meyers, a professor of physics at Princeton University who was not part of the research team, said the finding is the "sort of crack" that "has been sought for many, many years."
that explains it all to me...
electromagnetic != weak (Score:1)
The frequency of collisions told scientists about the electromagnetic forces that affect how neutrinos behave -- the so-called weak forces.
Actually, since neutrinos have no charge, electromagnetic forces have NO effect on them. The second half of the sentence is correct, it is the weak force that is acting here, which is a nuclear force, not an electromagnetic one.
Phyisics primer for the interested: there are 4 fundamental forces of nature (in increasing order of strength): gravity, electromagnetic, weak nuclear (keeps electrons in orbit around atomic nuclei), and strong nuclear (keeps atomic nuclei from flying apart).
- jonathan.
Those of us from Santa Cruz already know this... (Score:1)
New force discovered. (Score:1)
Blood Sport (Score:2, Interesting)
"Mathematics and Physics are the last true blood sports. Kill one bird an EVERYTHING goes."
Funny when you realise the ramifications of this since ALOT of work needs to be reevaluated, etc, even when the results are "statistically" correct, since the explinations and models of how things achieved some result are now totally different.
-Tim
The paper (Score:1)
http://arXiv.org/find/hep-ex/1/au:+McFarland/0/1/
hep-ex/0104037 "Observation of an Anomalous Number of Dimuon Events in a High Energy Neutrino Beam."
Schrodinger's Cat, or Nonlocality... Anyone? (Score:1)
Popular Science (Score:1)
Re:Theory (Score:1)
--death_denied(User#533148)
Re:How to get your lab mentioned in the media... (Score:1, Offtopic)
Re:This says nothing (Score:1)
Re:Not much content in this post... (Score:1)